Eva made 420 cookies and shortbreads. After she gave 0.7 of the cookies and 0.6 of the shortbreads to her boys, she was left with an equal number of cookies and shortbreads. How many cookies had she left?
| |
Cookies |
Shortbreads |
Before
|
10x2 =
20 u |
5x3 =
15 u |
Change
|
- 7x2 =
- 14 u |
- 3x3 =
- 9 u |
After
|
3x2 =
6 u |
2x3 =
6 u |
Comparing cookies and
shortbreads in the end |
1x6 =
6 u |
1x6 =
6 u |
0.7 =
710 0.6 =
610 =
35 The number of cookies and shortbreads is the same in the end. Make the number of cookies and shortbreads in the end the same. LCM of 3 and 2 and 1 is 6.
Total number of cookies and shortbreads at first
= 20 u + 15 u
= 35 u
35 u = 420
1 u = 420 ÷ 35 = 12
Number of cookies that Eva had left
= 6 u
= 6 x 12
= 72
Answer(s): 72
