Problem 5
The sum of two numbers is 175
Let the two numbers be x and y
Therefore x + y = 175
Their difference is = x - y and is equal to 19
x + y = 175
x - y = 19 Add
2x = 194 Divide by 2
x = 194/2
x = 97
x + y = 175
97 + y = 175
y = 175 - 97
y = 78
Problem 4
Let the nickels = N
Let the Pennies = P
N + P = 199 (1)
0.05*N +0.01 P = 7.67 Multiply the entire equation by 100
5N + P = 767 (2) Multiply equation (1) by 5 and subtract.
5N +5P =995
- 4P = - 228 Divide by -4
P = 57
N + P = 199
N + 57 = 199
N = 199 - 57
N = 142
Answer
Pennies = 57
Nickels = 142
Check
142*5 + 57*1 = ? 767
710 + 57 = ? 767
767 = 767