The three scores are 86, 74, and an unknown score x. The average (i.e. the sum divided by how many there are) is 80, so we have
Multiply both sides by 3 and you get
Subtract 160 from both sides to get
Note: you could solve this exercise very quickly if you notice that the two numbers, 86 and 74, are symmetrical with respect to 80, which is the average. So, the third number must be the average.
Interest on interest, or compound interest, is the adding of interest to the principal sum of a loan or deposit. Mike's account balance after 21 years is $69,131.44.
<h3>What is compound interest?</h3>Interest on interest, or compound interest, is the adding of interest to the principal sum of a loan or deposit. It's the outcome of reinvesting interest rather than paying it out so that interest is received on the principal plus previously collected interest in the next quarter.,
where A is the final amount
P is the principal amount
r is the rate of interest
n is the number of times interest is charged in a year
t is the number of years
The principal amount that Mike invested is $29,000. The rate of interest is 7.24% compounded daily, for 21 years. Therefore, the account balance after 21 years is
= $69,131.44
Hence, Mike's account balance after 21 years is $69,131.44.
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Answer:
7.5 gallons
Step-by-step explanation:
Given:
The Thomas family went for a Sunday drive.
Before they left, Mr. Thomas noticed the gas tank was ¾ full.
When they returned home the gas tank was ⅓ full.
Total capacity of the gas tank = 18 gallons
<u>Question asked:</u>
How many gallons of gas did the car use on the drive?
<u>Solu</u>tion:
Before they left, quantity of gas in the tank =
When they returned, quantity of gas in the tank =
Quantity of gas used on the drive = 13.5 - 6 = 7.5 gallons
Therefore, 7.5 gallons of gas used on the drive by Thomas family.