Posted by TIM on Wednesday, February 20, 2008 at 5:57pm.
PAULA ,SIMON AND RANDY COLLECTED INSECTS FOR THEIR SCIENCE PROJECT. AT THE END OF THE FIRST WEEK PAULA AND RANDY TOGETHER HAD 89 INSECTS, RANDY AND SIMON TOGETHER HAD 80 INSECTS, PAULA AND SIMON HAD TOGETHER HAD 85. HOW MANY DID EACH HAVE ALONE?

Math  Damon, Wednesday, February 20, 2008 at 7:01pm
P + R = 89
R + S = 80
P + S = 85
combine the first two equations by subtraction
P  S = 9
add that to the third
2 P = 94
P = 47
S = P9 = 38
R = 80  S = 42
check that
P+R = 47+42 = 89 yes
R+s = 42+38 = 80 yes
P+S = 47+38 = 85 yes