Reggie has some white and green marbles. The total mass of all his marbles is 219 g. He has 5 more green marbles than white marbles. The average mass of the white marbles is 9 g. The average mass of the green marbles is 15 g. How many marbles does Reggie have altogether?
| |
White |
Green |
Total |
| Number |
1 u |
1 u + 5 |
2 u + 5 |
| Value |
9 |
15 |
|
| Total value |
9 u |
15 u + 75 |
219 |
Total mass of white marbles
= 1 u x 9
= 9 u
Total mass of green marbles
= 15(1 u + 5)
= 15 u + 75
Total mass of the marbles
= 9 u + 15 u + 75
= 24 u + 75
24 u + 75 = 219
24 u = 219 - 75
24 u = 144
1 u = 144 ÷ 24 = 6
Total number of marbles
= 2 u + 5
= 2 x 6 + 5
= 12 + 5
= 75
Answer(s): 75
