Question

divide 36 into two parts such a way that 4/7 of a part is equal to 2/5 of other part

Answer 1

let one part be x
another will be (36 - x)
=> 4/7 of (36-x) = 2/5 of x
=> 4(36-x)/7  = 2x/5
on solving this we get, 
       => x=15
       => 36-15 = 21
so the two parts of 36 will be 15 and 21

Answer 2

let first part is x then other part is 36-x
acc to ques
4x/7=2(36-x)/5
4x/7=72-2x/5
20x=7 (72-2x)
20x=504-14x
34x=504
find the value of x
then the part is x nd 36-x