A carpenter was told to make a rectangular desk with top of dimension 50cm by...

MATHEMATICS
WAEC 1990

A carpenter was told to make a rectangular desk with top of dimension 50cm by 40cm. The carpenter actually made the desk 60cm by 35cm.

(a) Calculate the percentage error in the (i) length and the breadth ; (ii) area of the table top.

(b) Find the product of the two errors in a(i).

Explanation

Error in length = 60cm - 50cm = 10cm

Error in breadth = 40cm - 35cm = 5cm

(i) % error in length = \(\frac{10}{50} \times 100% = 20%\)

% error in breadth = \(\frac{5}{40} \times 100% = 12.5%\)

(ii) Area of the actual table = \(50cm \times 40cm = 2000cm^{2}\)

Area of the table in error = \(60cm \times 35cm = 2100cm^{2}\)

Error in area = \(2100cm^{2} - 2000cm^{2} = 100cm^{2}\)

% error in area = \(\frac{100}{2000} \times 100% = 5%\)

(b) Product of the error in length and in breadth = \(20 \times 12.5 = 250%\)



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