Question

Beth and Amy are trading marbles. Beth has three times more marbles than her sister, Amy.

The equation given below shows this relationship, where x represents the number of marbles Beth has, and y represents the number of marbles Amy has.



If Beth has 21 marbles, how many marbles does Amy have?
A.
6
B.
18
C.
7
D.
63

Answer 1

8

Explanation:

To find how many marbles Amy has, substitute 16 for x and solve for y.

X=2y

16=2y

16 -/- 2=2y -/-2

8=y

So, Amy has 8 marbles.

Answer 2

The answer is c which is 7.

Explanation:

3 times so,

21 / 3 = 7

Hopes this helps.