JAMB - Mathematics (1987 - No. 16)
The formula Q = 1.5 + 0.5n gives the cost Q(in Naira)of feeding n people for a week. Find (in kobo) the extra cost of feeding one additional person
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Uitleg
To find the extra cost of feeding one additional person, we start with the formula for the cost \( Q \):
\(Q = 1.5 + 0.5n\)
Calculate the cost for \( n \)
\(Q(n) = 1.5 + 0.5n\)
Calculate the cost for \( n + 1 \)
\(Q(n + 1) = 1.5 + 0.5(n + 1) = 1.5 + 0.5n + 0.5 = 2 + 0.5n\)
Find the extra cost
\(\text{Extra cost} = Q(n + 1) - Q(n) = (2 + 0.5n) - (1.5 + 0.5n) = 2 - 1.5 = 0.5\)
The extra cost of feeding one additional person is \( 0.5 \) Naira.
To convert this to kobo (since \( 1 \) Naira = \( 100 \) kobo):
\(0.5 \text{ Naira} = 0.5 \times 100 = 50 \text{ kobo}\)
Thus, the extra cost of feeding one additional person is \( 50 \) kobo.