Explanation

Semi was 21 years old in 1945

The number of years from 1945 to 1965 is 20 years.

21 + 20 = 41

Explanation

We know that in a dictionary, words are arranged in alphabetical order.

First, we will arrange the letters of the word MOTHER in alphabetical order

Thus, we get E, H, O, M, R, and T.

Now, we know that the words starting with E will appear first in the dictionary.

Let us fix letter E as the first letter of the word.

Explanation

A farad (F) is the standard unit of capacitance (C) in the International System of Units (SI).

***

The SI unit of energy/work is the joule (J)

Explanation

Explanation

Raza is ranked ninth from the top. That means there are 8 students above Raza.

Raza is 38th from the bottom. That means there are 37 students below him.

So total students 8 + Raza + 37 = 46 students

Explanation

6,

6×6=36,

7,

7×7=49,

5, 

5 x 5 = 25

Explanation

Now Maryam was shifted to 4 places to the right.

This implies her place is x+4 from left now, but it is given that her new place is 12th from left.

Now, in a row of 21 girls, her place is 8,

which is 14th place from right.

Explanation

A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z.

ANPL 

BOOK 

the next alphabet of A is B, N is O,

the before alphabet of P is O, K is L

so 

GZOE 

HAND 

the next alphabet of G is H, Z is A

the before alphabet of N is O, D is E

Explanation

Total no. of students = Top position + Bottom position - 1

Total no. of  students =16+49−1

                                      = 64

****

Number of students in the class $=(15+1+48)=64$

Explanation

Let the required number of labourers be x

Less working hour/day, More labours (Indirect proportion)

More days, fewer labourers (Indirect proportion)