When Carly does 15 push-ups and 10 sit-ups, it takes a total of 35 seconds. In comparison, she needs 57 seconds to do 19 push-ups and 19 sit-ups. How long does it take Carly to do each kind of exercise.

Guest Feb 3, 2020

#1**+1 **

15 p + 10 s = 35

19 p + 19 s = 57 Simultaneous equations....2 unknowns 2 equations

Mutiply eq 1 by - 1.9

-28.5 p - 19 s = -66.5 add to second equation

-9.5 p = -9.5

p = 1 second

then YOU should be able to calculate how long a sit up takes !

ElectricPavlov Feb 3, 2020