Question

On Monday, Peter ran 20 minutes and walked 20 minutes and he burnt 500 calories. On Tuesday, Peter ran 10 minutes and walked 35 minutes and he burnt, again, 500 calories.

a) Create two equations based on the situation.
b) Determine the value of the variables.
c) How many calories can peter burn with one hour of running?

Answer 1

a) 20r + 20w = 500, 10r + 35w = 500

b) r = 15, w = 10

c) 900 calories

Step-by-step explanation:

Let running time be r, walking time be w

a) Hence, make equation's:

20r + 20w = 500... equation 1

10r + 35w = 500... equation 2

b) Determine the value of the variables by solving simultaneously.

⇒ (500 - 20w)/20 = (500 - 35w)/10

cross multiply

⇒ 10(500 - 20w) = 20(500 - 35w)

multiply

⇒ 5000 - 200w = 10000 - 700w

shift sides

⇒ -200w + 700w = 10000 - 5000

simplify

⇒ 500w = 5000

divide both sides by 500

⇒ w = 10

Now find the value of variable r,

⇒ r = (500 - 20w)/20

insert w = 10

⇒ r = (500 - 20(10))/20

simplify

⇒ r = 15

Hence the value of r is 15 and w is 10

c) Find calories burnt after one hours of running: [1 hours = 60 minutes]

calories = 60r = 60(15) = 900 calories

Hence, he can burn 900 calories after one hours of running.