grade 7 parent

Checking on son's homework, want to make sure correct.

  1. Joseph is planting bushes around the perimeter of his lawn. If the bushes must be planted 4 feet apart and Joseph's lawn is 64 feet wide and 124 feet long, how many bushes will Joseph need to purchase?

  2. The cost of a long distance phone call is $1.50 for the first two minutes and $0.60 for each additional minute. How much will Maria pay for a 24 minute phone call?

  3. Find the next three numbers in the pattern. 1,3,7,15,31,___,____,___.

Thank you

Hi Brenba,
  1. Think about actually planting the bushes. Start along a side of length 64 ft. Dig a hole at one end and plant the bush. Move 4 feet, dig a hole and plant a bush. Continue until you reach the corner. Since 64/4 = 16 you have moved 16 times and dug 17 holes, the first hole and then 16 more.

    Turn the corner. The corner bush is already there so move 4 feet and dig a hole. Continue along this side until you reach the corner. Since 124/4 = 31, you have dug 31 holes.

    Turn the corner and do the third side digging 16 holes and then turn the corner again to the fourth side. On the last side which is 124 ft long you only need 30 holes since the first bush you planted is the last bush along this side. Thus you need

    17 + 31 + 16 + 30 = 94 bushes.

  2. The first 2 minutes costs $1.50 and then there are 22 minutes remaining, each of which costs $0.60. Hence the total cost is

    $1.50 + 22($0.60) = $14.70

  3. Each term is one more than twice the previous term.
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