The question asks us to solve for the ratio of pennies (p) to dimes (d).
INSUFFICIENT: This tells us that the ratio of nickels (n) to dimes (d) is 3:2.
This gives us no information about the ratio of pennies to dimes.
INSUFFICIENT: This tells us that there is $7, or 700 cents in the piggy bank.
We can write an equation for this as follows, using the value of each type of
coin: 10d + 5n + p = 700. This is not enough information for us to figure out
the ratio of p to d.
(1) AND (2) INSUFFICIENT: Taken together, both statements still do not
provide enough information for us to figure out the ratio of p to d. For
example, there may be 3 nickels, 2 dimes, and 665 pennies in the piggy bank
(this keeps the ratio of nickels to dimes at 3:2 and totals to $7). Alternatively,
there may be 30 nickels, 20 dimes, and 350 pennies (this also keeps the ratio
of nickels to dimes at 3:2 and totals to $7). In these 2 cases the ratio of pennies
to dimes is not the same.
The correct answer is E.