AlgebraMediumTwo quantities from a relation and a weighted sum
Algebra practice question
A shelf holds novels and atlases. There are 5 more atlases than novels, and three times the number of novels plus twice the number of atlases is 50. How many novels are there?
Answer: 8
Let novels be n: 3n + 2(n + 5) = 50, so 5n + 10 = 50 and n = 8.
Common wrong answers
- If you answered 10
- 10 comes from 5n = 50, forgetting the 10 from the atlases' extra 5.
- If you answered 12
- 12 comes from 5n = 60 (adding 10 instead of subtracting).
- If you answered 13
- 13 is the number of atlases.
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