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JAMB Mathematics Past Questions & Answers - Page 36

176.

Express the product of 0.0014 and 0.011 in standard form 

A.

1.54 x 102

B.

1.54 x 103

C.

1.54 x 102

D.

1.54 x 105

Correct answer is D

No explanation has been provided for this answer.

177.

The equation of the line in the graph is 

A.

3y = 3x + 12

B.

3y = 3x + 12

C.

3y = -4x + 12

D.

3y = -4x + 9

Correct answer is C

Gradient of line = Change in yChange in x = y2Yx2x 

y2  = 01 

Y1  = 4 

x2  = 3 and x1  = 0

y2y1x2x1=0430=43

Equation of straight line y = mx + c

Where m = gradient and c = y 

intercept = 4 

y = 4x + 43 multiply through y 

3y = 4x + 23 

178.

A number is selected at random between 20 and 30, both numbers inclusive. Find the probability that the number is a prime. 

A.

211

B.

511

C.

611

D.

811

Correct answer is A

Possible outcomes are 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. Prime numbers have only two factors, itself and 1. The prime numbers among the group are 23, 29. 

The probability of choosing a prime number 

= Number of PrimeNo. of Total Possible Outcome

= 211

179.

 Calculate the standard deviation of the following data: 7, 8, 9, 10, 11, 12, 13 

A.

2

B.

4

C.

12

D.

17

Correct answer is A

x x - x (x - x)2

7

8

9

10

11

12

13

 

-3

-2

-1

0

1

2

3

 

9

4

1

1

0

4

9

--------------

28

 

S.D = (xx)2N=d2N=287 

= 4 

= 2

180.

If N225.00 yields N27.00 in x years simple interest at the rate of 4% per annum, find x. 

A.

3

B.

4

C.

12

D.

17

Correct answer is A

Principal = N225.00, interest = N27.00

Year = x, Rate = 4% 

1 = PRT100

27 = 225×4×x100 = 2700 = 900T

T = 2700900 

= 3 years