The ratio is used for comparing two quantities of the sane kind.

The ratio formula for two numbers says a and b is given by a:b or a/b. When two or more such ratios are equal, they are said to be in proportion.

The concept of ratio and proportion is majorly based on ratios and fractions.  

Solution:

From the question it is given that,

Monthly income of a man = ₹ $5,000$

Every month man saves ₹ $800$

(i) Annual expenses to annual income,

Annual income = monthly income $\times 12$

= ₹ $5,000\times 12$

= ₹ $60,000$

Then, monthly expenses = ₹ $5,000-800$

= ₹ $4,200$

Annual expenses = monthly expenses $\times 12$

= ₹ $4,200\times 12$

= ₹ $50,400$

Annual expenses/Annual income

Therefore, Annual expenses: annual income $=21:25$

(ii) Monthly savings to monthly expenses,

Monthly expenses = ₹ $5,000-$₹ $800=$ ₹ $4,200$

Then, monthly savings/monthly expenses

Therefore, monthly savings: monthly expenses $4:21$