There are 105 balls in a box. 0.2 of them are silver balls, and the rest are grey and brown balls. If there are 15 as many grey balls as brown balls. How many brown balls are there?
| Silver balls |
Grey balls |
Brown balls |
Total |
| 1 u |
4 u |
5 u |
| |
1 p |
5 p |
|
0.2 =
210 =
15 Fraction of balls that are grey and brown balls
= 1 -
15 =
45 Total number of balls = 5 u
5 u = 105
1 u = 105 ÷ 5 = 21
Number of grey balls and brown balls
= 4 u
= 4 x 21
= 84
Number of grey and brown balls
= 1 p + 5 p
= 6 p
6 p = 84
1 p = 84 ÷ 6 = 14
Number of brown balls
= 5 p
= 5 x 14
= 70
Answer(s): 70
