JAMB Mathematics Past Questions & Answers - Page 211

1,051.

In the equation below, Solve for x if all the numbers are in base 2: \(\frac{11}{x}\) = \(\frac{1000}{x + 101}\)

A.

101

B.

11

C.

110

D.

111

E.

10

Correct answer is B

\(\frac{11}{x}\) = \(\frac{1000}{x + 101}\) = 11(x + 101)

1000x = 11x + 1111

1000x - 11x = 1111

101x = 1111

x = \(\frac{1111}{101}\)

x = 11

1,052.

A sum of money was invested at 8% per annum simple interest. If after 4 years the money amounts to N330.00. Find the amount originally invested

A.

N180.00

B.

N165.00

C.

N150.00

D.

N250.00

E.

N200.00

Correct answer is D

S.I = \(\frac{PTR}{100}\)

T = 4yrs, R = 8%, a = N330.00

330 - P = \(\frac{PTR}{100}\), A = P + I

i.e. A = P + \(\frac{PTR}{100}\)

330 = P + \(\frac{P(4) (8)}{100}\)

33000 = 32P + 100p

132P = 33000

P = N250.00

1,053.

Arrange the following numbers in ascending order of magnitude \(\frac{6}{7}\), \(\frac{13}{15}\), 0.8650

A.

\(\frac{6}{7}\) < 0.865 < \(\frac{13}{15}\)

B.

\(\frac{13}{15}\) < \(\frac{6}{7}\) < 0.865

C.

\(\frac{6}{7}\) < \(\frac{13}{15}\) < 0.865

D.

0.865 < \(\frac{6}{7}\) < \(\frac{13}{15}\)

Correct answer is A

\(\frac{6}{7}\), \(\frac{13}{15}\), 0.8650

In ascending order, we have 0.8571, 0.8650, 0.8666

i.e. \(\frac{6}{7}\) < 0.8650 < \(\frac{13}{15}\)

1,054.

If three numbers P, Q, R are in ratio 6 : 4 : 5, find the value of \(\frac{3p - q}{4q + r}\)

A.

\(\frac{3}{2}\)

B.

\(\frac{2}{3}\)

C.

2

D.

3

Correct answer is B

P : Q : r = 6 : 4 : 5

5 = 6 + 4 + 5

= 15

P = \(\frac{6}{15}\), q = \(\frac{4}{15}\), r = \(\frac{5}{15}\) = \(\frac{1}{3}\)

To find \(\frac{3p - q}{4q + r}\)

3p - q = 3 x \(\frac{6}{15}\) - \(\frac{4}{15}\)

\(\frac{18}{15}\) - \(\frac{4}{15}\) = \(\frac{14}{15}\)

∴ 4q + r = 4 x \(\frac{4}{15}\) + \(\frac{5}{15}\)

\(\frac{16}{15}\) = \(\frac{16}{15}\) + \(\frac{5}{15}\)

= \(\frac{21}{15}\)

\(\frac{14}{15}\) x \(\frac{15}{21}\) = \(\frac{14}{21}\)

= \(\frac{2}{3}\)