David had 2 bags of marbles. After he had sold 44 marbles from Bag
X to his friend, the number of marbles in Bag Y was 5/7 of the number
of marbles in Bag X. Given that there were 2/5 as many marbles in Bag Y
as in Bag X originally, find the number of marbles in Bag X at first.

solution:

let Number of marbles in bag X = x

and number of marbles in Bag Y = y

According to question ,

** y = 2/5 x .... (Given Original Condition)**

After David sold 44 marbles from Bag X ,

number of marbles in Bag X = **x - 44 **

y = 5/7 (x - 44) .............. (given)

Substitute y = 2/5x in above equation , we get

2/5x = 5/7 (x -44)

2x/5 = 5x/7 - 5*44/7

5x/7 - 2x/5 = 5*44/7

by cross Multiplication ,

25x - 14x /(5*7) = 220/7

11x /35 = 220 /7

11x = 35*220/7

11x = 5*220

x = 5*220 /11

x = 5*20

x = 100

**Hence total Number of Marbles in Bag X is 100 .**

Hope this helps You!!!

If You feel This worthy for the best Answer.Then Plz make it best answer !!!

Thank You!!