The number of sit-ups Micah does is the sum of twice a number and 25. The number of sit-ups Micah does is also 3 times the number minus 25. How many sit-ups does Micah do?

125 Sit-ups.

Step-by-step explanation:

Let y equal the number of sit-ups and x equal the unknown number.

y=2x+25 Sum of twice a number and 25.

y=3x-25 3 times the number minus 25.

Use Substitution:

2x+25=3x-25

x=50

This is the unknown number.

To solve for y, just plug the x value in.

y=2 (50) + 25

y=125

So, Micah did 125 sit-ups.