John and Tommy have a total of 56 buttons. If John gives Tommy 21 buttons, Tommy will have 3 times as many buttons as him. Find
(a) John's buttons
(b) Tommy's buttons
|
John |
Tommy |
Total |
Before |
1 u + 21 |
3 u - 21 |
56 |
Change |
- 21 |
+ 21 |
|
After |
1 u |
3 u |
4 u |
(a)
Total number of buttons
= 1 u + 3 u
= 4 u
4 u = 56
1 u = 56 ÷ 4 = 14
Number of buttons that John has
= 1 u + 21
= 14 + 21
= 35
(b)
Number of buttons that Tommy has
= 56 - 35
= 21
Answer(s): (a) 35; (b) 21