math problem
posted by Mark on .
 Mr. Hermann, a stamp collector , sold 2 stamps for $5000 each. Based on his cost , he made a 25% profit on one stamp and lost 20% on the other stamp. What was Mr. Hermann's total loss on the two transactions?
 There are five chidren in the Roberts family. Amy and Ariel are twins. Brett and Bart are also twins. Amy's age plus Brett's age is 25years. Ariel's age plus Charlene's age is 27 years . Bart's age plus Charlene's age is 20 years. What is the sum of the ages of all 5 children in the Roberts fanily?

return = 5000(1.25) + 5000(.8)
= ...
#2
let Amy and Ariel' age be x
let Brett and Bart's age be y
let Charlene's age be z
x+y = 25
x + z = 27
y+z = 20
2nd minus the third
x  y = 7
add that to the first
2x = 32
x=16
in the 1st:
16+y = 27
y = 11
in the third:
11+z = 20
z = 9
so we have 2x + 2y + z
= 32+22+9 = 63 
Amy and Ariel are 13 + 13=26.Brett and Bart are 12+12=23.Charlene is 24