Question

The cost $C$ of sending a parcel post package weighing $P$ gms, $P$ an integer is $Rs.10$ for the first grams and $Rs.3$ for each additional grams. The formula for the cost is

• A. $C=10+3P$
• B. $C=10P+3$
• C. $C=10+3(P-1)$
• D. $C=9+3P$
• E. $C=10P-7$

Answer 1

The correct option is C $C=10+3(P-1)$

For $P-1$ gms the charge is $3$ rupees per grams. For the first gram the charge is $10$ rupees. $\therefore C=10+3(P-1)$; or
The charge for each gram is $3$ rupees with an additional charge of $7$ rupees for the first gram. $\therefore C=3P+7=3P-3+10=10+3(P-1)$.