$7.56 is the answer to your question
Step-by-step explanation:

8 nickels, because 8 (nickels) × 5 (worth) = 40
24 dimes, because 8 × 3 = 24 24 × 10 = 240
240 + 40 = 280
Oh. It's rounding. So, for example, depending what you were told to round to, the second problem would be 760-330=430
Answer:
1877 computer users
Step-by-step explanation:
We have that for 95% of confident, the value of z has a value of 1.96 (attached table about it), they also mention the margin of error (E) that is 10 and finally the standard deviation (sd) that has a value of 221.
We apply the following formula:
n = [z * sd / E] ^ 2
replacing:
n = [1.96 * 221/10] ^ 2
n = 1876.27
that is, the minimum sample size is 1877