Perry has some blue and pink marbles. The total mass of all his marbles is 184 g. He has 9 less blue marbles than pink marbles. The average mass of the blue marbles is 6 g. The average mass of the pink marbles is 8 g. How many marbles does Perry have altogether?
| |
Blue |
Pink |
Total |
| Number |
1 u |
1 u + 9 |
2 u + 9 |
| Value |
6 |
8 |
|
| Total value |
6 u |
8 u + 72 |
184 |
Total mass of blue marbles
= 1 u x 6
= 6 u
Total mass of pink marbles
= 8(1 u + 9)
= 8 u + 72
Total mass of the marbles
= 6 u + 8 u + 72
= 14 u + 72
14 u + 72 = 184
14 u = 184 - 72
14 u = 112
1 u = 112 ÷ 14 = 8
Total number of marbles
= 2 u + 9
= 2 x 8 + 9
= 16 + 9
= 72
Answer(s): 72
