Trisha has a bag with 32 dimes and nickels worth $2.80. how many of each coin does she have?

A) D + N = 32

B) .1D + .05N = 2.80 multiplying A) by -.1

A) -.1D -.1N = -3.2  then adding this to B)

-.05N = -.4

Nickels = 8   Dimes = 24

DOUBLE-CHECK

.1 * 24 + .05 * 8 = 2.80 ||| 2.40 + 40 = 2.80

mr. flanders’ class sold 47 doughnuts and   mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations: