Risa is 30% heavier than Tommy. Winnie is 10% lighter than Tommy. Risa is 12 kg heavier than Winnie. What is Tommy's mass?
| Risa |
Tommy |
Winnie |
| 130% |
100% |
|
| |
100% |
90% |
| 13 u |
10 u |
9 u |
Risa's mass compared to Tommy's mass in percent
= 100% + 30%
= 130%
Winnie's mass compared to Tommy's mass in percent
= 100% - 10%
= 90%
130% =
130100 =
131090% =
90100 =
910Tommy's mass is the repeated identity. Make Tommy's mass the same.
Tommy's mass = 10 u
Mass that Risa has more than Winnie
= 13 u - 9 u
= 4 u
4 u = 12
1 u = 12 ÷ 4 = 3
Tommy's mass
= 10 u
= 10 x 3
= 30 kg
Answer(s): 30 kg
