Question

A told B, ' if you give me two marbles we will have equal number of marbles with us' B told A, If you give me three marbles, I will have twice the number of marbles that are with you. ' how many does B have??

Answer 1

B has 11 marbles at first and A has 7 marbles
when B gave 2 marbles to A, B was left with 9 marbles and A has 9 marbles
when A gave 3 marbles to B B has 12 marbles
and A was left with 6 marbles
6×2=12

Answer 2

Heya,

Number of marbles with A be "x" & B be "y".

case 1

x + 2 = y - 2
x - y = - 4

Case 2

y + 3 = 2 ( x - 3 )
y + 3 = 2 x - 6
2 x - y = 9

By Elimination method..... ,

2 x - y = 9
x - y = -4
(-) (-) (+)
----------------
x = 13
----------------

Substituting x = 13 in equation ( 1 )
y = 13 + 4
y = 17

B has 17 marbles.....

Hope this will help you!! : )