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JAMB Mathematics Past Questions & Answers - Page 206

1,026.

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

101

110

111

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

1,027.

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

N180.00

N165.00

N150.00

N250.00

N200.00

View answer & explanation

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

1,028.

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

$\frac{6}{7}$ < 0.865 < $\frac{13}{15}$

$\frac{13}{15}$ < $\frac{6}{7}$ < 0.865

$\frac{6}{7}$ < $\frac{13}{15}$ < 0.865

0.865 < $\frac{6}{7}$ < $\frac{13}{15}$

View answer & explanation

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 < $\frac{13}{15}$

1,029.

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

$\frac{3}{2}$

$\frac{2}{3}$

View answer & explanation

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 $\frac{15}{21}$ = $\frac{14}{21}$

= $\frac{2}{3}$