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JAMB Mathematics Past Questions & Answers - Page 222

1,106.

A train moves from P to Q at an average speed of 90km/h and immediately returns from Q to P through the same route at an average speed of 45km/h. Find the average speed for the entire journey

55.00km/h

60.00km/h

67.50km\h

75.00km\h

View answer & explanation

Correct answer is C

Average speed from P to Q = 90km\h

Average speed from O to P = 45km/h

Average for the entire journey = 90 + 45

$\frac{135}{2}$ = 67.50 km/h

1,107.

Reduce each number to two significant figures and then evaluate $\frac{0.021741 \times 1.2047}{0.023789}$

0.8

0.9

1.1

1.2

View answer & explanation

Correct answer is C

$\frac{0.021741 \times 1.2047}{0.023789}$ = $\frac{0.022 \times 1.2}{0.024}$ (to 216)

= $\frac{0.0264}{0.024}$

= 1.1

1,108.

A rectangular lawn has an area of 1815 square yards. if its length is 50 meters, find its width in meters given that 1 metre equals 1.1 yards

39.93

35.00

33.00

30.00

View answer & explanation

Correct answer is D

1m = 1.1 yard, length(L)= 50m

= (50 x 1.1)yards

= 55 yards

Area(A) = length(L) y width (W)

1815 = 55y width (W)

width (w) = $\frac{1815}{55}$

= 33 yards

But 33 yards = 30 meters

1,109.

Find the least length of a rod which can be cut into exactly equal strips, each of either 40cm or 48cm in length

120cm

240cm

360cm

480cm

View answer & explanation

Correct answer is B

The least length is $\frac{40}{48}$ = $\frac{5}{8}$

for the rod to be cut in exactly equal trips

Ratio $\frac{5}{6}$ : $\frac{48}{40}$

$\frac{\frac{5}{6}}{\frac{40}{48}}$ = 1

$\frac{5}{6}$ x $\frac{48}{40}$ = $\frac{240}{240}$ = 1

The least length = 240cm

1,110.

Convert 241 in base 5 to base 8,

71₈

107₈

176₈

241₈

View answer & explanation

Correct answer is B

241₅ = 2 x 5² + 4 x 5 + 1 x 5 + 1 x 5^o

50 + 20 + 1 = 71₁₀

Convert 71₁₀ to base 8
$\begin{array}{c|c} 8 & 71 \\ 8 & 8 R 7\\8 & 1 R 0\\8 & 0 R 1\end{array}$

= 107₈