Directions: Using the digits 1 to 9, at most one time each, fill in the boxes to find the largest or smallest possible values fo

Question

Ronch [10]

3 years ago

13

Directions: Using the digits 1 to 9, at most one time each, fill in the boxes to find the largest or smallest possible values fo

r the sum of X and Y.

Mathematics

2 answers:

12345 [234] · Answer 1 · 2022-04-06T08:16:53+03:00

9514 1404 393

Answer:

smallest: 8x -3 = 4; 1y +9 = 2. total = -49/8

largest: 1x -9 = 8; 2y +3 = 7. total = 19

Step-by-step explanation:

If we use variables to represent the box contents, we can write ...

ax -b = c
dy +e = f

Then the values of x and y are ...

x = (c +b)/a

y = (f -e)/d

For positive integer values of the variables, x will always be positive, and y may or may not be negative.

<h3>Smallest sum</h3>

For the sum to be the smallest, we must have x be as small as possible and the ratio (f-e)/d be as negative as possible.

x will be small for large 'a' and for (c+b) small. For y to be as negative as possible, we want 'd' and 'f' small and 'e' large. Best results are obtained for

8x -3 = 4 ⇒ x = 7/8
1y +9 = 2 ⇒ y = -7

For these coefficients, the sum is -6 1/8 = -49/8.

(note that the values of 'b' and 'c' can be swapped with no net effect)

<h3>Largest sum</h3>

For the sum to be the largest, we must have x as large as possible: (b+c) large and 'a' small. At the same time we must have y be positive and as large as possible: (f-e) positive and large, 'd' small. Best results are obtained for