There are 180 balls in a bag. 0.1 of them are black balls, and the rest are brown and grey balls. If there are 15 as many brown balls as grey balls. How many grey balls are there?
| Black balls |
Brown balls |
Grey balls |
Total |
| 1 u |
9 u |
10 u |
| |
1 p |
5 p |
|
0.1 =
110 =
110 Fraction of balls that are brown and grey balls
= 1 -
110 =
910 Total number of balls = 10 u
10 u = 180
1 u = 180 ÷ 10 = 18
Number of brown balls and grey balls
= 9 u
= 9 x 18
= 162
Number of brown and grey balls
= 1 p + 5 p
= 6 p
6 p = 162
1 p = 162 ÷ 6 = 27
Number of grey balls
= 5 p
= 5 x 27
= 135
Answer(s): 135
