Sally is reading a book that has 590 pages. She already read some of it last week. She plans to read 50 pages tomorrow. By then, she will be 1/5 of the way through the book. How many pages did Sally read last week?

Answer:Sally read 68 pages last week.

Step-by-step explanation:

Let x represent the number of pages that Sally read last week. The book has a total of 590 pages. She already read some of it last week.

She plans to read 50 pages tomorrow and by then, she will be 1/5 of the way through the book. This means that the total number of pages that she would have read by tomorrow would be

1/5 * 590 = 118

It means that the sum of the number of pages that she read last week and the 50 pages that she planned to read tomorrow is 118. Therefore

50 + x = 118

x = 118 - 50 = 68