The cost of 32 pens and 12 pencils is £790. What is the total cost (in £) of 8 pens and 3 pencils together?
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Answer: (B) 197.5
Explanation
Let the cost of one pen be x and the cost of one pencil be y. According to the problem, the cost of 32 pens and 12 pencils is given by the equation 32x + 12y = 790. We need to determine the value of 8x + 3y. By observing the coefficients, we can see that 8 is one-fourth of 32, and 3 is one-fourth of 12. Therefore, we can divide the entire original equation by 4 to find the required value:
(32x + 12y)/(4) = ⁷⁹⁰⁄₄
8x + 3y = 197.5
The total cost of 8 pens and 3 pencils is £197.5.