You burn 20 calories per minute biking for x minutes and 10 calories per minute walking for y minutes. You spend a total of 80 minutes biking and walking and burn 1140 calories.
a. Write a system of equations to determine how much time you spend on each exercise.
b. How many minutes did you spend biking?

Step-by-step explanation:

1140 divided by 10

let soccer = x and golf = y

part a

1st equation: x + y = 125

2nd equation: x = y +45

part b

replace x in the 1st equation with the 2nd one:

y + 45 + y = 125

simplify:

2y + 45 = 125

subtract 45 from each side:

2y = 80

divide both sides by 2:

y = 80/2

y = 40

she plays golf for 40 minutes.

part c

no because she plays soccer for 45 minutes longer than golf 40 +45 =   85 minutes, not 80 minutes.