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WAEC Mathematics Past Questions & Answers - Page 130

646.

An empty rectangular tank is 250cm long and 120cm wide. If 180 litres of water is poured into the tank. Calculate the height of the water

A.

6.0cm

B.

5.5cm

C.

5.0cm

D.

4.5cm

Correct answer is A

Volume of water in tank = l x b x h = 180 litres

but 1 litre = 1000cm2

250 x 120 x hw = 180 x 1000

hw = 180×1000250×120

= 6cm

647.

Solve the inequality: 3(x + 1) 5(x + 2) + 15

A.

x -14

B.

x - 14

C.

x -11

D.

x - 11

Correct answer is C

3(x + 1) 5(x + 2) + 15

3x + 3 5x + 10 + 15

3x - 5x 10 + 15 - 3

-2x 22

x 222

x -11

648.

Given that = {x: -2 < x 9}, where x is an integer what is n(T)?

A.

9

B.

10

C.

11

D.

12

Correct answer is C

T = {-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9}

n(T) = 11

649.

The sum of 6 and one-third of x is one more than twice x, find x

A.

x = 7

B.

x = 5

C.

x = 3

D.

x = 2

Correct answer is C

6 = 13x = 1 + 2x

6 = 1 = 2x1x3

5 = 6xx3=5x3

5 = 5x3

3 x 5 = 5x

15 = 5x

x = 155

= 3

650.

Given that P = {x : 1 x6}, and Q = {x : 2 x10} where x is an integer. Find n(P Q)

A.

5

B.

6

C.

8

D.

10

Correct answer is A

P = {1, 2, 3, 4, 5, 6}; Q = {3, 4, 5, 6, 7, 8, 9}

P Q) = {2, 3, 4, 5, 6}

n(P Q) = 5