Aplumber charges an initial amount to make a house call plus an hourly rate for the time he is working. a 1-hour job costs $90 and a 3-hour job $210. what is the initial amount and the hourly rate that the plumber charges

the initial amount is $30

The hourly rate is $60

Step-by-step explanation:

Let x represent the fixed cost or the initial amount to make a house call.

Let y represent the amount that the plumber charges per hour.

A 1-hour job costs $90. It means that

x + y = 90

x = 90 - y- - - - - - - - - - 1

A 3-hour job cost $210. This means that

x + 3y = 210 - - - - - - - - - - - - -2

Substituting equation 1 into equation 2, it becomes

90 - y + 3y = 210

90 + 2y = 210

2y = 210 - 90 = 120

y = 120/2 = 60

Substituting y = 60 into equation 1, it becomes

x = 90 - 60 = 30

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

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