SOLUTION: There are between 50 and 100 books on a shelf. Exactly 20% of them are textbooks. Exactly 1/7 of them are novels. How many books are on the shelf?

Question 721761: There are between 50 and 100 books on a shelf. Exactly 20% of them are textbooks. Exactly 1/7 of them are novels. How many books are on the shelf?
Answer by josgarithmetic(39630) (Show Source): You can put this solution on YOUR website!
This relies on the search for whole numbers such that 20% gives a whole number and 1/7 gives a whole number. 70 fits this. You can look in the multiples of 7, and choose from the ones between 50 and 100. This is more effective than setting up equations and and use of .
RELATED QUESTIONS
Mia has four math books, three novels and two books of poetry. She wants to arrange them (answered by sudhanshu_kmr)

A book store has received 8 different books, of which 3/8 are novels, 25% are study... (answered by Boreal)

There are 8 Physics books, 4 calculus books, 7 us history textbooks, and 3 resource books (answered by stanbon)

There are 8 physics textbooks, 7 us history textbooks, 4 calculus textbooks, and 3... (answered by solver91311)

There are 8 physics textbooks, 7 us history textbooks, 4 calculus textbooks, and 3... (answered by stanbon)

Suppose you have 30 books (15 novels, 10 history books, and 5 math books). Assume that... (answered by math_helper)

Betty has 20 different books. A. If 4 books are selected from these 20 books, how many... (answered by Boreal)

Betty has 20 different books. Among the 20 books, 12 are classic novels, 6 are Science... (answered by ewatrrr)

Five different algebra textbooks, two different calculus textbooks, and four different... (answered by stanbon,math_helper)