Question

Scott burned 20 calories per minute jogging for x minutes and 5 calories per minute for biking for y minutes. He spent a total of 120 minutes jogging and biking and burned 1,2oo calories. The system of equations shown can be used to determine how much time Scott spent on each exercise. What is the value of x, the minutes Scott spent jogging? 20x+5y=1200 x+y=120

Answer 1

x = 112

Explanation:

We can create two equations 1. one that calculates calories burned and 2.another that calculates minutes:

20*x + 5*y = 1200

x + y = 120

Then we can solve for x

x = 120 - y

then we can plug that into the top equation:

20(120 - y) + 5y = 1200

divide by 5:

4(120 - y) + y = 240

distribute:

480 - 4y + y = 240

and then do all that combining like factors what not and simplify and solve:

480 - 3y = 240

-3y = -240

y = 8

NOW WE CAN JUST PLUG IN THE ANSWER FOR Y TO FIND X

8+x =120

x = 112