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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 $ * 6 7 . 9 * 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.

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5 votes

Answer:

The first digit = m = 3

The last digit = n = 2

Explanation:

We are told in the question that

Brryn's grand pa gave her a store receipt that listed 72 identical items, each the same price, for a total cost of $ * 67.9*

The first step we have to take is to multiples of 72

One of them is 8 and 9

Where,

9 × 8 = 72

Let us represent:

the first digit covered by m

the last digit covered by n

Second step

We find the last covered digit

For a number to be divided by 8, one of the important characteristics of the number is that is one of the multiples of 8

From price:

The last 3 digits =

79* =

We create number in multiples of 8 that can give us 7.9*

7.9* = 7.20 + 0.64+ 0.08

7.9* = 7.92

Hence, the last digit is 2

Third step

We find the first covered digit.

For a number to be divisible by 9, one of its important characteristics as well is that is it a multiple of 9

The first digit = m is determined as:

= m + 6 + 7 + 9 + 2

= m + 24

= m + 24

The multiple of 9 nearest to 24 is 27

Hence,

27 = m + 24

m = 27 - 24

m = 3

Therefore,

The first covered digit = m = 3

The last covered digit = n = 2

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