SEE BELOW⬇
Explanation:
Let A represent the number of brand A calculators purchased, and B represent the number of brand B calculators purchased.
We have two pieces of information:
- The cost of each brand A calculator is $80, and the cost of each brand B calculator is $95.
- The total cost of all calculators is $1780.
We can write two equations based on this information:
- 80A + 95B = 1780 (total cost equation)
- A + B = 20 (total number of calculators equation)
↪ Now, we can solve this system of equations. Let's use the second equation (A + B = 20) to express one of the variables in terms of the other. Let's solve for A:
Now, substitute this expression for A into the first equation (80A + 95B = 1780):
Now, distribute 80:
Combine like terms:
Now, divide by 15 to find B:
So, the department purchased 12 brand B calculators.
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➡ To find the number of brand A calculators, use the equation A = 20 - B:
∴ department purchased 8 brand A calculators.