Olivia baked a total of 392 cupcakes and tarts. After giving away 90% of the tarts and 80% of the cupcakes, she was left with twice as many tarts as cupcakes. Find the number of cupcakes Olivia gave away.
| |
Tarts |
Cupcakes |
| Before |
10x2 =
20 u
|
5 u |
| Change |
- 9x2 =
18 u |
- 4 u |
| After |
1x2 =
2 u |
1 u |
Comparing tarts and
cupcakes in the end |
2x1 =
2 u |
1x1 =
1 u |
90% =
90100 =
91080% =
80100 =
45The number of tarts in the end is the repeated identity. Make the number of tarts in the end the same. LCM of 1 and 2 is 2.
Total number of pastries at first
= 20 u + 5 u
= 25 u
25 u = 392
1 u = 392 ÷ 25 = 6
Number of cupcakes that Olivia gave away
= 4 u
= 4 x 6
= 24
Answer(s): 24
