78.50=1.50x+.50y when x+y=87

A bookcase has two shelves. The top shelf has 10 more than 1/3 the number of books on the bottom shelf. There are 12 books on the bottom shelf how many books are on the top shelf

David wants to buy a game system and his favorite game. The game costs $25 and is 1/5 of the price of the game system. How much does the game system cost?

What is the product of 11/15 and 12/7?

John can cut the yard on a riding lawn mower in 2 hours. Sandy can cut the yard with a push mower in 5 hours. How long would it take to cut the yard if John and Sandy work together? (Express in hours and minutes)

Marlon and Brent are each measuring one of their shoes their shoes measure 11 inches in all. Marlon shoes is 1 inch longer than Brents shoe how long is Brents shoe?

How many atoms are there in the world

What is x equal? 5x+7

How do you factor a monomial

Simplify 6-3a + 10b^2 - 2a - 4b^2 - 3

There are eight pieces of pizza. Marco ate three-eighths of the pizza for lunch. He ate another two-eighths of the pizza for dinner. How much of the pizza has he eaten in all? A. 1⁄2 B. 3⁄8 C. 5⁄8 D. 7⁄8