Linear Equations in One Variable

SAT Math· difficulty 4/5

An office orders pens at \2eachandpencilsateach and pencils at$0.50each.Theyorder100itemsforeach. They order 100 items for$80$. How many pens?

  • A

    20

    check_circle
  • B

    40

  • C

    30

  • D

    10

Explanation

a+b=100a + b = 100, 2a+0.5b=802a + 0.5b = 80. Sub: 2a+0.5(100a)=802a + 0.5(100-a) = 801.5a=301.5a = 30a=20a = 20.

Want 10 more like this — adaptive to your weak spots?

Related questions