Question

weights of two friends A and B are in the ratio of 1:2. A's weight increased by 20 % and the total weight of A And B becomes 60 kg, with an increase of 30 %. By what percent the weight of B increase?
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Answer 1

Answer:

30℅

Explanation :

Let weight of A is x then weight of B will be 2x .

Now

x is increased by 20℅ = x + x (20/100) = 6x/5

So

$\frac{ 6 x}{5} + 2x = 60 \\16 x =5 \times 60 \\ x = \frac{75}{4} \\ and \: \: weight \: \: of \: b = 2x = {75 \over2}kg$

now if x is increased by 30℅

$= x \times \frac{130}{100} = \frac{75}{4} \times \frac{13}{10} = \frac{195}{8}$

Now new weight of B = 2x = 195/4

Change in weight of B

$= \frac{195}{4} - \frac{75}{2} = \frac{45}{4}$

So percentage change will be

$\frac{( \frac{45}{4}) }{( \frac{75}{2}) } \times 100 = 30\%$