Question 781:

• WAEC 2021

A body of mass 15kg is placed on a smooth plane which is inclined at 60° to the horizontal. If the box is at rest,
calculate the normal reaction to the plane. [ Take g = 10m/s\(^2\) ]

A. 129.9N
B. 75N
C. 60.0N
D. 7.5N

Question 782:

• WAEC 2021

A fair die is tossed 60 times and the results are recorded in the table

Number of die	1	2	3	4	5	6
Frequency	15	10	14	2	8	11

Find the probability of obtaining a prime number.

A. \(\frac{7}{30}\)
B. \(\frac{1}{6}\)
C. \(\frac{7}{15}\)
D. \(\frac{8}{15}\)

Question 783:

• WAEC 2021

If 2y\(^2\) + 7 = 3y - xy, find \(\frac{dy}{dx}\)

A. \(\frac{-y}{4x+y-3}\)
B. \(\frac{y}{4x+y-3}\)
C. \(\frac{-y}{4x+x-3}\)
D. \(\frac{y}{4x+x-3}\)

Question 784:

• WAEC 2021

Three forces, F\(_1\) (8N, 030°), F\(_\2) (10N, 150° ) and F\(_\3) ( KN, 240° )are in equilibrium. Find the value of N

A. 5√3
B. 6√2
C. 6√3
D. 9√3

Question 785:

• WAEC 2021

In △PQR, \(\overline{PQ}\) = 5i - 2j and \(\overline{QR}\) = 4i + 3j. Find \(\overline{RP}\).

A. -i - 5j
B. -9 - j
C. I + 5j
D. -9i + j