Use the substitution method to for "m" p+(2p+11)=53 3p+11=53 3p=42 p=14
Put "p" into either equation to solve for "m" m=2(14)+11 m=28+11 m=39
Check by plugging both "p" and "m" into both equations to make sure they work: 14+39=53 53=53 That one works, now let's check the other one 39=2(14)+11 39=28+11 39=39 They both work! Petra is 14 years old, and her mother is 39 years old