At first, Tom had thrice as many lollipops as Zeph. After they each gave away 20 lollipops, Tom had 7 times as many lollipops as Zeph. How many lollipops did they have altogether at first?
| |
Tom |
Zeph |
Difference |
| Before |
3x3 =
9 u |
1x3 =
3 u |
2x3 =
6 u |
| Change |
- 20 |
- 20 |
|
| After |
7 u |
1 u |
6 u |
Since they both gave away the same number of lollipops, their difference in the number of lollipops remains the same. Make the difference in the number of lollipops the same. LCM of 2 and 6 is 6.
Number of lollipops that each gave away
= 9 u - 7 u
= 2 u
2 u = 20
1 u = 20 ÷ 2 = 10
Number of lollipops that they had altogether at first
= 9 u + 3 u
= 12 u
= 12 x 10
= 120
Answer(s): 120
