The commissions for the rates Rs400, Rs700, Rs1000 do not follow an easy pattern so you would need to have a formula relating the commission to the rate. If done by Excel IF statements, then the statement would be:
=IF(B3<400,101,IF(B3<700,121,(IF(B3<1000,151,B3*B3/18000+B3/45+92)))) where B3 happens to be the cell reference for the rate value. Note in this case that, if the rate is 1000 or more, the statement just returns a calculated commission according to a formula based on the given figures. For an indefinite rate value, see below, which uses a simple formula in place of a compound conditional statement.
If the cutoff for Rs1000 were 141 instead of 151, then there is no need for an IF statement because a simple formula will suffice for an indefinite range of rates:
=101+20*INT((INT(RATE/100-1)/3)) where RATE represents the cell reference for the rate value. The INT function replaces the conditional statements.
For example, if the rate cell contained Rs587, we would have 101+20*INT((INT(587/100)-1)/3)). Breaking this down:
101+20*INT((5-1)/3)=101+20*INT(4/3)=101+20*1=121, because Rs587 is between 400 and 700. The IF statement confirms that the commission would be Rs121.
If rate=Rs3000 the commission would be Rs281:
101+20*INT((INT(3000/100)-1)/3))=
101+20*INT((30-1)/3)=
101+20*INT(29/3)=
101+20*9=101+180=281.
The formula is clearly more flexible, but depends on a simple relationship between rate and commission. There is insufficient information in this question to establish such a relationship. The best would be a quadratic relationship.