Explanation

Circumference =2πr.

∴2πr=31.4.

2×3.14×r=31.4.

r=5cm.

Area =πr2.

Area =3.14×(25)2

=78.5cm2.

Explanation

Work done by 8 men or 12 women in 25 days:

Work done by 8 men in 25 days = 1 complete piece of work.

Work done by 12 women in 25 days = 1 complete piece of work.

Explanation

Explanation

0.057−0.041=0.016

Explanation

Explanation

Explanation

Explanation

The symbol used to denote the proportionality is '∝'.

For example, if we say, a is proportional to b, then it is represented as “a ∝ b”

Explanation

To find the ratio of 12 minutes to 1 hour, we first convert 1 hour into minutes:

1 hour = 60 minutes.

Now, the ratio of 12 minutes to 60 minutes is:

12​/ 60= 1/ 5​

Explanation

Now let's evaluate the options:

(A) ab: This string matches $ab^*$ (since $b^*$ allows for one 'b'). So, this belongs to $\mathrm{R<b\; style="color:\; rgb(0,\; 0,\; 0);\; font-family:\; Overpass,\; sans-serif;\; font-size:\; 0.875rem;"><br></b>}$

(B) abb: This string also matches ab∗ (since $b^*$ allows for two 'b's). So, this belongs to $R$.

(C) cb: This string matches cb∗ (since $b^*$ allows for one 'b'). So, this belongs to $R$.

(D) All of these: Since all the previous options (A, B, C) belong to $R$, this is correct.