Jar B has 20% more marbles than jar A. What percent of the marbles in jar B have to be moved to jar A, in order that the number of marbles in each jar will be the same?

Question

Can you please help me with this question?

Answer 1

Here's another couple of simple solutions.

A=100%

B=120%

(100%+120%)/2=220%/2=110% in each jar

this means 10% was moved to jar A

10%/120%=1/12=0.08333...=8.333...%

OR,...

simply omit the % symbols

A=10, B=12

10+12=22

22/2=11

1 was moved from B to A

1/12=8.333...%

Answer 2

Let B = marbles in Jar B, and A the marbles in Jar A.

If B is 20% more than A, B = 1.2A

We will move x marbles from Jar B to Jar A so that the marbles in Jar B equal the marbles in Jar A.

Thus, B - x = A + x

1.2A - x = A + x

.2A = 2x

x = .1A

Then, what percent of B's marbles are removed.

We remove .1A of 1.2A marbles. This is .1A/1.2A of the marbles in B, or 1/12 of the marbles.

1/12 = y/100, so 12y = 100, y = 8 1/3

8 1/3% or 8.3333% (I don't know the solutions to choose from).