General Mathematics Paper 2, Nov/Dec. 2015

QUESTION 2
(a)   If   +  = , calculate the value of x.

(b)  A trader bought some bags of rice and some bags of beans for sale in

his shop. Each bag of rice cost N2,250.00 while each bag of beans cost   N2,400.00.  If he bought 17 bags altogether and paid N39,600.00, how many bags of beans did he buy? 

Observation

 

The Chief Examiner reported that although this question was attempted by majority of the candidates, their performance was poor. In part (a), majority of the candidates were reported not to clear the fractions correctly. They were expected to respond as follows:

 

LCM of denominators = 2x(x + 3). Multiplying through by the LCM gave
2(x + 3) + 2x = x(x + 3) which further simplified to x2 – x – 6 = 0. Solving this equation gave x = -2 and 3.

 

In part (b), the performance was reported to be poorer than in part (a). Majority of the candidates were reported not to translate the word problem correctly to obtain the expected equations. Candidates were expected to show that if x = number of bags of beans and y = number of bags of rice, then from the second statement, 2250y + 2400x = 39600 or 225y + 240x = 3960 (eqn. 1). Also, from the third statement, x + y = 17 (eqn. 2). Solving the two equations simultaneously gave the number of bags of beans = x = 9.