Seth has some blue and yellow marbles. The total mass of all his marbles is 183 g. He has 9 more yellow marbles than blue marbles. The average mass of the blue marbles is 3 g. The average mass of the yellow marbles is 4 g. How many marbles does Seth have altogether?
| |
Blue |
Yellow |
Total |
| Number |
1 u |
1 u + 9 |
2 u + 9 |
| Value |
3 |
4 |
|
| Total value |
3 u |
4 u + 36 |
183 |
Total mass of blue marbles
= 1 u x 3
= 3 u
Total mass of yellow marbles
= 4(1 u + 9)
= 4 u + 36
Total mass of the marbles
= 3 u + 4 u + 36
= 7 u + 36
7 u + 36 = 183
7 u = 183 - 36
7 u = 147
1 u = 147 ÷ 7 = 21
Total number of marbles
= 2 u + 9
= 2 x 21 + 9
= 42 + 9
= 36
Answer(s): 36
