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# Problem of the week

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Bryn’s Grandpa is always creating math problems for her to solve. In one problem, he gave her a store receipt that listed 72 identical items, each the same price, for a total cost of \$ *67.9*.  * is the missing number. Bryn’s Grandpa covered the first and last digits of the total price on the receipt with stars. Determine the values of the digits that Bryn’s Grandpa covered.

Oct 1, 2020

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Bryn’s Grandpa is always creating math problems for her to solve. In one problem, he gave her a store receipt that listed 72 identical items, each the same price, for a total cost of \$ *67.9*.  * is the missing number. Bryn’s Grandpa covered the first and last digits of the total price on the receipt with stars. Determine the values of the digits that Bryn’s Grandpa covered.

#67.9&   must be exactly divisible by 72.       72=2*2*2*9

a) Since it is divisible by an even number, what do you know about &  ??

b)  A number is divisible by 9 if the digits add up to a number that is divisible by 9.

so ....                   6+7+9+  # + & = 9k               k is an integer, greater that 0

15      +  # + & = 9k
# + & = 9k -6

# + & = 5 or  14

This has taken it down to 5 possibilities.

Which of those are divisible by 8?

You can take if from there.

Oct 1, 2020