Explanation

First, let's convert 2 years to months:

2 years = 24 months

Now, the ratio is:

18 months : 24 months

= 3 : 4

Explanation

Let's solve this:

Work = Force × Time (or Workers × Days)

28 workers × 26 days = x workers × 13 days

x = (28 × 26) / 13

x = 56 workers

Explanation

2 days = 48 hours

Ratio = 12 hours : 48 hours

= 1 : 4

Explanation

Inverse proportion: more days, fewer employees

24 employees × 20 days = x employees × 40 days

x = (24 × 20)/40

x = 12

Explanation

Explanation

Explanation

Given: Time downstream is half the time upstream.

Let:

- Speed of boat in still water = b

- Speed of current = c

Speed downstream = b + c  

Speed upstream = b - c

Time ∝ 1 / Speed

Given: Time downstream = (1/2) × Time upstream  

=> 1/(b + c) = (1/2) × 1/(b - c)  

=> 2/(b + c) = 1/(b - c)  

=> 2(b - c) = b + c  

=> 2b - 2c = b + c  

=> 2b - b = c + 2c  

=> b = 3c  

=> b : c = 3 : 1

Explanation

Convert minutes to seconds:

2 minutes = 2 × 60 = 120 seconds

Ratio = 120 seconds : 600 seconds

= 1 : 5

Explanation

M1 × D1 = M2 × D2

16 × 20 = M2 × 40

M2 = (16 × 20)/40

M2 = 8

Explanation

Convert to same units:

10 minutes = 600 seconds

Ratio = 600 : 240

= 5 : 2