JAMB - Mathematics (2021)

1
Solve the following equation: \(\frac{2}{(2r - 1)}\) - \(\frac{5}{3}\) =  \(\frac{1}{(r + 2)}\)
Answer
(B)
( 1, - \(\frac{5}{2}\) )
2
In how many ways can 2 students be selected from a group of 5 students in a debating competition?
Answer
(B)
10 ways
3
What is the rate of change of the volume V of a hemisphere with respect to its radius r when r = 2?
Answer
(A)
4
determine the maximum value of y=3x\(^2\) + 5x - 3
Answer
(D)
No correct option
5

A trapezium has two parallel sides of lengths 5cm and 9cm. If the area is 91cm\(^2\), find the distance between the parallel sides

Answer
(A)
13 cm
6
find the value of p if the line which passes through (-1, -p) and (-2,2) is parallel to the line 2y+8x-17=0?
Answer
(D)
2
7
The ratio of the length of two similar rectangular blocks is 2 : 3. If the volume of the larger block is 351cm\(^3\), then the volume of the other block is?
Answer
(A)
234.00 cm3
8
Find the derivative of the function y = 2x\(^2\)(2x - 1) at the point x = -1?
Answer
(B)
16
9
Correct 241.34(3 x 10\(^{-3}\))\(^2\) to 4 significant figures
Answer
(D)
0.002172
10
Find the mean deviation of 1, 2, 3 and 4
Answer
(A)
1.0
11
At what rate would a sum of N100.00 deposited for 5 years raise an interest of N7.50?
Answer
(C)
1.5%
12
Three children shared a basket of mangoes in such a way that the first child took \(\frac{1}{4}\) of the mangoes and the second \(\frac{3}{4}\) of the remainder. What fraction of the mangoes did the third child take?
Answer
(A)
\(\frac{3}{16}\)
13
Simplify and express in standard form \(\frac{0.00275 \times 0.00640}{0.025 \times 0.08}\)
Answer
(C)
8.8 x 10-3
14
Simplify \(\sqrt{27}\) + \(\frac{3}{\sqrt{3}}\)
Answer
(A)
4\(\sqrt{3}\)
15
Three brothers in a business deal share the profit at the end of a contract. The first received \(\frac{1}{3}\) of the profit and the second \(\frac{2}{3}\) of the remainder. If the third received the remaining N12000.00 how much profit did they share?
Answer
(B)
N54 000.00
16
P(-6, 1) and Q(6, 6) are the two ends of the diameter of a given circle. Calculate the radius.
Answer
(A)
6.5 units
17
The angle of a sector of a circle, radius 10.5cm, is 48°, Calculate the perimeter of the sector
Answer
(D)
29.8cm
18
Find the length of a side of a rhombus whose diagonals are 6cm and 8cm
Answer
(B)
5cm
19
Each of the interior angles of a regular polygon is 140°. How many sides has the polygon?
Answer
(A)
9
20
A cylinder pipe, made of metal is 3cm thick.If the internal radius of the pipe is 10cm.Find the volume of metal used in making 3m of the pipe.
Answer
(D)
20 700\(\pi\)cm3
21
The locus of a point which moves so that it is equidistant from two intersecting straight lines is the?
Answer
(B)
angle bisector of the two lines
22
4, 16, 30, 20, 10, 14 and 26 are represented on a pie chart. Find the sum of the angles of the bisectors representing all numbers equals to or greater than 16
Answer
(D)
276o
23
The mean of ten positive numbers is 16. When another number is added, the mean becomes 18. Find the eleventh number
Answer
(C)
38
24
Two numbers are removed at random from the numbers 1, 2, 3 and 4. What is the probability that the sum of the numbers removed is even?
Answer
(B)
\(\frac{1}{2}\)
25
Find the probability that a number selected at random from 41 to 56 is a multiple of 9
Answer
(A)
\(\frac{1}{8}\)
26
Musa borrows N10.00 at 2% per month simple interest and repays N8.00 after 4 months. How much does he still owe?
Answer
(C)
N2.80
27
Simplify 2log \(\frac{2}{5}\) - log\(\frac{72}{125}\) + log 9
Answer
(D)
1 - 2log 2
28
A car travels from calabar to Enugu, a distance of P km with an average speed of U km per hour and continues to benin, a distance of Q km, with an average speed of Wkm per hour. Find its average speed from Calabar to Benin
Answer
(B)
\(\frac{uw(p + q)}{pw + qu}\)
29
If w varies inversely as \(\frac{uv}{u + v}\) and w = 8 when

u = 2 and v = 6, find a relationship between u, v, w.
Answer
(C)
uvw = 12(u + v)
30
If g(x) = x\(^2\) + 3x  find g(x + 1) - g(x)
Answer
(B)
2(x + 2)
31
factorize m\(^3\) - m\(^2\) + 2m - 2
Answer
(D)
(m2 + 2)(m - 1)
32
The angles of a quadrilateral are 5x-30, 4x+60, 60-x and 3x+61.find the smallest of these angles​
Answer
(C)
60 - x
33
What is the n-th term of the sequence 2, 6, 12, 20...?
Answer
(C)
n2 + n
34
If the binary operation \(\ast\) is defined by m \(\ast\) n = mn + m + n for any real number m and n, find the identity of the elements under this operation
Answer
(D)
e = 0
35
Factorize completely 81a\(^4\) - 16b\(^4\)
Answer
(C)
(3a - 2b)(3a + 2b)(9a2 + 4b2)