Asked by Mary

If a penny prior to 1982 weighted 3.1 grams and a current one weighs 2.5 grams how many pennies weighing 3.1 and 2.5 will I need in a combination of ten in total to have 25 grams??
Answered by Scott
x + y = 10

3.1 x + 2.5 y = 25

solves easily by inspection (observation)
Answered by Mary
Thanks , that's exactlywhat I thought, but did something wrong when solving and thought I was wrong .
THANKS!!