Answer:
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.