Expert: Lynn Houston - 5/4/2009

Question
1) When Ms. Marley was three times as old as Jennie, they were seven years younger than they are now.  Now Ms. Marley is twice as old as Jennie.  How old are they?

2) Jacob has pennies, nickels and dimes.  he has a total of $3.60.  There are twice as many pennies as nickels and twice as many nickels as dimes.  How many of each coin does Jacob have?

Answer
1) When Ms. Marley was three times as old as Jennie, they were seven years younger than they are now.  Now Ms. Marley is twice as old as Jennie.  How old are they?

m = marley's age now
j = jennie's age now

2j = m
3(j-7) = m-7

3j - 21 = 2j-7
j = 14
m = 28


2) Jacob has pennies, nickels and dimes.  he has a total of $3.60.  There are twice as many pennies as nickels and twice as many nickels as dimes.  How many of each coin does Jacob have?

.01p + .05n + .1d = 3.60
2n = p
2d = n  (d = n/2)

.01(2n) + .05n + .1n/2 = 3.60
.07n + .1n/2 = 3.60
.14n + .1n = 7.20
.24n = 7.2
n = 30 ($1.50)
p = 60 ($ .60)
d = 15 ($1.50)