Need help wit hwork: if u're good at math please help me?

Question

1) the perimetee of sportsland park is 624 yd. the length of the rectangular park is 8 yd. more than 3 times the width. what are the dimensions?

2) two alternative bands depart in two separate buses from San Francisco heading in opposite directions (one to LA and one to Seattle). The LA bus is going around 55 mi/hr. The Seattle bus is going around 45 mi/hr. They will lose contract with each other over their bus radios when they are 400 miles apart--how long will it take for them to be 400 miles apart?

thnk you for helping

Answer 1

1)

Start off by saying what you know. You know that a perimeter is going to be the four sides: two widths and two lengths.

P = perimeter, L = length, W = width

P = 2L + 2W

L = 3W + 8

P = 624

Now substitute in (3W + 8) for L to reduce the equation to one with only two variables.

P = 2L + 2W

P = 2(3W + 8) + 2W

P = 6 W + 16 + 2W

P = 8W + 16

From here, you can substitute this value of P into the other equation with P to get a numeric value for W.

P = 624

8W + 16 = 624

8W = 608

W = 76

Substitute the numeric value of W in for W so you can compare L by itself to a numeric value and find the answer.

P = 2L + 2W

624 = 2L + 2(76)

312 = L + 76

236 = L

L = 236

So the dimensions are 236 ft. in length and 76 ft. in width.

2)

This one is easier. You know the distance between the buses increases by the sum of 45 and 55 miles every hour.

D = 55h + 45h

D = h(55 + 45)

D = h(100)

h(100) = D

h = D/100

h = 400/100

h = 4

So it takes 4 hours.