Answer:
350 - 170 - 120 = r
Step-by-step explanation:
Identify the variable:
r = number of red pens
The total amount of pens ordered is 350 when adding all three colors of pens. This means we must add all of the colored pens to find the total number of pens, 350.
Write this as an equation:
170 + 120 + r = 350
Rewrite the equation to find r:
350 - 170 - 120 = r
12+48+36=96, it only says that there are one in each box so that means you only have to add them once.
He would drive 585 miles in 13 hours