Howard has some red and pink marbles. The total mass of all his marbles is 196 g. He has 8 less red marbles than pink marbles. The average mass of the red marbles is 7 g. The average mass of the pink marbles is 11 g. How many marbles does Howard have altogether?
| |
Red |
Pink |
Total |
| Number |
1 u |
1 u + 8 |
2 u + 8 |
| Value |
7 |
11 |
|
| Total value |
7 u |
11 u + 88 |
196 |
Total mass of red marbles
= 1 u x 7
= 7 u
Total mass of pink marbles
= 11(1 u + 8)
= 11 u + 88
Total mass of the marbles
= 7 u + 11 u + 88
= 18 u + 88
18 u + 88 = 196
18 u = 196 - 88
18 u = 108
1 u = 108 ÷ 18 = 6
Total number of marbles
= 2 u + 8
= 2 x 6 + 8
= 12 + 8
= 88
Answer(s): 88
