Question

Jar B has 20% more marbles than jar A. What percent of marbles should be moved from jar A to jar B so that jar B will double jar A in number of marbles

Answer 1

let x be the percent of marbles removed from jar A, then

B = 1.2A
B + Ax = 2(A - Ax )

1.2A + Ax = 2(A - Ax)
1.2A + Ax = 2A - 2Ax
Ax + 2Ax = 2A - 1.2A
x(3A) = 0.8A
x = 0.8A/3A
x = 0.26666....

so about 26.67%