A Boy Weighs 40 Kilos And One Fifth Of His Own Body Weight. What Does He Weigh?
can u make it simple for me to understand… not this /4 x3 lingo
thanks you!
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10 Responses to “A Boy Weighs 40 Kilos And One Fifth Of His Own Body Weight. What Does He Weigh?”
The Undertaker (RIP) on October 30th, 2009 at 3:59 pm
Let his total weight be ‘x’
x = 40 + (x/5)
x = (40*5 + x)/5
5x = 200 + x
4x = 200
x = 50
haans42 on October 30th, 2009 at 10:34 pm
OK, this question is written in a way to make you confused. Silly but what can you do?
Change the question to:
A boy weighs 40kg *plus* one fifth of his own body weight.
You actually want to figure out how much a fifth of his body weight is, so you can add it to the 40kg.
You need to convert this to fractions. In other words:
The boy weighs one fifth of his body weight plus four fifths of his body weight.
Now you have to make a giant leap and realize that 40 kg is actually four fifths of his body weight! So you divide 40 by 4 and you have an answer of 10 kg for one fifth of his body weight!
Now you add one fifth and four fifths to get five fifths or 50kg
If you have to convert this into some solve for X formula you are making it too complicated. It is a trick question because of the way it is worded and converting into a solve for X formula will give you a headache. Once you understand the question and can do it for other fractions you can begin to convert it into the abstract solve for X type problem
For example: A boy weighs 50Kg plus half his own body weight. How much does the boy weigh.
X=50kg+1/2X
Then there are about 10 intermediate steps to show that this is really X=50kg+50kg= 100kg
The quickest way to get past this is to recognize the question as actually asking this:
If 50kg is one half the boys weight how much does he weigh?
Or in the case of your original question:
If 40Kg is four fifths of the boys weight, how much does he weigh?
This gets around the trickery of the wording.
If he weighs 40 kilos and one fifth, then the 40 kilos must be the other 4 fifths.
if 4 fifths is 40 kilos, then 1 fifth must be 10 kilos
so he weighs 40 + 10 = 50 kilos all together
40kilos + 1/5 = 1 whole or 5/5
5/5 – 1/5 = 40kilos.
Now do the math you can see 5/5-1/5 = 4/5
so 4/5 =40 kilos.
Now you have to find out the missing number 1/5 represents. If you divide 40 kilos into four equal parts you will get each part weighing 10 kilos (40 / 4 = 10)
Therefore each part or each 1/5 is 10 kilos
so add 1/5 or 10 kilos to the 4/5 or 40kilos and you get 50 kilos
arun on October 31st, 2009 at 9:04 pm
a boy weights = 40kg
own body = one fifth
so 40multiply by one fifth 40×1/5 5 cuts 40 as 8 times so 8×1=8 so 40+8 is 48
ans wer is 48
nancy on October 31st, 2009 at 11:21 pm
his weight is 40 + 40 * (1 / 5)
x.Hannah on November 1st, 2009 at 5:33 am
48 kilos
1/5 into 40 is 8, add 8 to 40 and voilla! lol
Let his total weight be ‘x’
x = 40 + (x/5)
x = (40*5 + x)/5
5x = 200 + x
4x = 200
x = 50
OK, this question is written in a way to make you confused. Silly but what can you do?
Change the question to:
A boy weighs 40kg *plus* one fifth of his own body weight.
You actually want to figure out how much a fifth of his body weight is, so you can add it to the 40kg.
You need to convert this to fractions. In other words:
The boy weighs one fifth of his body weight plus four fifths of his body weight.
Now you have to make a giant leap and realize that 40 kg is actually four fifths of his body weight! So you divide 40 by 4 and you have an answer of 10 kg for one fifth of his body weight!
Now you add one fifth and four fifths to get five fifths or 50kg
If you have to convert this into some solve for X formula you are making it too complicated. It is a trick question because of the way it is worded and converting into a solve for X formula will give you a headache. Once you understand the question and can do it for other fractions you can begin to convert it into the abstract solve for X type problem
For example: A boy weighs 50Kg plus half his own body weight. How much does the boy weigh.
X=50kg+1/2X
Then there are about 10 intermediate steps to show that this is really X=50kg+50kg= 100kg
The quickest way to get past this is to recognize the question as actually asking this:
If 50kg is one half the boys weight how much does he weigh?
Or in the case of your original question:
If 40Kg is four fifths of the boys weight, how much does he weigh?
This gets around the trickery of the wording.
If he weighs 40 kilos and one fifth, then the 40 kilos must be the other 4 fifths.
if 4 fifths is 40 kilos, then 1 fifth must be 10 kilos
so he weighs 40 + 10 = 50 kilos all together
x=40+1/5x
x-1/5x=40
4/5x=40
4x=40*5
x=200/4
x=50
1
— x 40 = 8
5
Thus,
his weight = 40 + 8 = 48 kg
let x be his weight
x=40 +x/5
x=50
40kilos + 1/5 = 1 whole or 5/5
5/5 – 1/5 = 40kilos.
Now do the math you can see 5/5-1/5 = 4/5
so 4/5 =40 kilos.
Now you have to find out the missing number 1/5 represents. If you divide 40 kilos into four equal parts you will get each part weighing 10 kilos (40 / 4 = 10)
Therefore each part or each 1/5 is 10 kilos
so add 1/5 or 10 kilos to the 4/5 or 40kilos and you get 50 kilos
a boy weights = 40kg
own body = one fifth
so 40multiply by one fifth 40×1/5 5 cuts 40 as 8 times so 8×1=8 so 40+8 is 48
ans wer is 48
his weight is 40 + 40 * (1 / 5)
48 kilos
1/5 into 40 is 8, add 8 to 40 and voilla! lol