Jeremy has some green and pink marbles. The total mass of all his marbles is 243 g. He has 7 more pink marbles than green marbles. The average mass of the green marbles is 8 g. The average mass of the pink marbles is 15 g. How many marbles does Jeremy have altogether?
| |
Green |
Pink |
Total |
| Number |
1 u |
1 u + 7 |
2 u + 7 |
| Value |
8 |
15 |
|
| Total value |
8 u |
15 u + 105 |
243 |
Total mass of green marbles
= 1 u x 8
= 8 u
Total mass of pink marbles
= 15(1 u + 7)
= 15 u + 105
Total mass of the marbles
= 8 u + 15 u + 105
= 23 u + 105
23 u + 105 = 243
23 u = 243 - 105
23 u = 138
1 u = 138 ÷ 23 = 6
Total number of marbles
= 2 u + 7
= 2 x 6 + 7
= 12 + 7
= 105
Answer(s): 105
