Emily baked a total of 399 cookies and biscuits. After giving away 80% of the biscuits and 75% of the cookies, she was left with five times as many biscuits as cookies. Find the number of cookies Emily gave away.
| |
Biscuits |
Cookies |
| Before |
5x5 =
25 u
|
4 u |
| Change |
- 4x5 =
20 u |
- 3 u |
| After |
1x5 =
5 u |
1 u |
Comparing biscuits and
cookies in the end |
5x1 =
5 u |
1x1 =
1 u |
80% =
80100 =
4575% =
75100 =
34The number of biscuits in the end is the repeated identity. Make the number of biscuits in the end the same. LCM of 1 and 5 is 5.
Total number of pastries at first
= 25 u + 4 u
= 29 u
29 u = 399
1 u = 399 ÷ 29 = 3
Number of cookies that Emily gave away
= 3 u
= 3 x 3
= 9
Answer(s): 9
