Dana had a total of 393 black and pink balls. She used
45 of her black balls and bought another 69 pink balls. The number of pink balls she had then become
14 the number of black balls. How many less pink balls than black balls did she have at first?
| |
Black balls |
Pink balls |
| Before |
5x4 |
|
| Change |
- 4x4 |
+ 69 |
| After |
1x4 |
|
| Comparing balls in the end |
4x1 |
1x1 |
| |
Black balls |
Pink balls |
| Before |
20 u |
1 u - 69 |
| Change |
- 16 u |
+ 69 |
| After |
4 u |
1 u |
The number of black balls in the end is repeated.
LCM of 1 and 4 is 4.
Total number of black balls and pink balls
= 20 u + 1 u - 69
= 21 u - 69
21 u - 69 = 393
21 u = 393 + 69
21 u = 462
1 u = 462 ÷ 21 = 22
Number of less pink balls than black balls at first
= 20 u - (1 u - 69)
= 19 u + 69
= 19 x 22 + 69
= 487
Answer(s): 487
