There are 140 marbles in a bag. 0.1 of them are silver marbles, and the rest are blue and black marbles. If there are 18 as many blue marbles as black marbles. How many black marbles are there?
| Silver marbles |
Blue marbles |
Black marbles |
Total |
| 1 u |
9 u |
10 u |
| |
1 p |
8 p |
|
0.1 =
110 =
110 Fraction of marbles that are blue and black marbles
= 1 -
110 =
910 Total number of marbles = 10 u
10 u = 140
1 u = 140 ÷ 10 = 14
Number of blue marbles and black marbles
= 9 u
= 9 x 14
= 126
Number of blue and black marbles
= 1 p + 8 p
= 9 p
9 p = 126
1 p = 126 ÷ 9 = 14
Number of black marbles
= 8 p
= 8 x 14
= 112
Answer(s): 112
