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WAEC Mathematics Past Questions & Answers - Page 18

86.

Three boys shared D 10,500.00 in the ratio 6:7:8. Find the largest share.

A.

4000

B.

5000

C.

4500

D.

3500

Correct answer is A

Total proportion is 6+7+8 = 21

61050021 = 3000

71050021 = 3500

81050021 = 4000

The largest share is 4000

87.

If a = 3 and b = -7, find the value of 5b+(a+b)2(ab)2

A.

0.51

B.

0.91

C.

-0.19

D.

-0.51

Correct answer is C

 5b+(a+b)2(ab)2

= 57+(3+7)2(37)2

=  35+16102

=  19100 or -0.19

88.

M varies directly as n and inversely as the square of p. If M= 3 when n = 2 and p = 1, find M in terms of n and p.

A.

3n2p2

B.

2n3p2

C.

2n3p

D.

3n22p2

Correct answer is A

M = nkp2 

k →  mp2n3x122

k =  32

:  m = 3xn2p2

89.

Find the 17term of the Arithmetic Progression (A.P):-6,-1,4

A.

-91

B.

-86

C.

74

D.

79

Correct answer is C

common difference d =  -1 - [-6] → -1 + 6

d = 5; a = -6

Tn = a + (n-1)d

: T17 = -6 + (17 - 1) 5 

→ -6 + (16)5

→ -6 + 80 = 74

90.

A weaver bought a bundle of grass for $ 50.00 from which he made 8 mats. If each mat was sold for $ 15.00, find the percentage profit.

A.

240%

B.

140%

C.

120%

D.

40%

Correct answer is B

cost price = $50

Selling price = 15 * 8 = $120

percentage profit = spcpcp * 100 →  1205050 * 100

percentage profit = 70 * 2 → 140%