math
posted by Connie (g/ma) on .
I am lost.
Question: Blake bought 21 books. The least he spent for a book was $18. The most he spent for a book was $25. What could be the amount that he ended up paying for his books?
a.$375
b.$530
c. $175
d. $445

Ahhh, great question!!!!
We know two of the prices, the high and the low, which is a total of $43.
So the average price of the remaining 19 books must be > $18 and < $25
(37543)/19 = 17.5 no good
(53043)/19 = 25.6 no good
(17543)/19 = 6.9 no good
(44543)/19 = 21.1 YUP!, that's it.