If 4(a + b) = 7, what is the value of a + b?

X+ y = 5 ; x - y =3 solve using linear combination

Emily is entering a bicycle race for charity. her mother pledges $0.90 for every 0.75 mile she bikes. if emily bikes 18 miles, how much will her mother donate?

Adeposit of 5500 at 6% for 3 years equals