There are 100 marbles in a box. 0.1 of them are pink marbles, and the rest are blue and grey marbles. If there are 15 as many blue marbles as grey marbles. How many grey marbles are there?
| Pink marbles |
Blue marbles |
Grey marbles |
Total |
| 1 u |
9 u |
10 u |
| |
1 p |
5 p |
|
0.1 =
110 =
110 Fraction of marbles that are blue and grey marbles
= 1 -
110 =
910 Total number of marbles = 10 u
10 u = 100
1 u = 100 ÷ 10 = 10
Number of blue marbles and grey marbles
= 9 u
= 9 x 10
= 90
Number of blue and grey marbles
= 1 p + 5 p
= 6 p
6 p = 90
1 p = 90 ÷ 6 = 15
Number of grey marbles
= 5 p
= 5 x 15
= 75
Answer(s): 75
