Question

Under the same 'Airtel One' plan, ISD calls to different groups of countries are billed at different per minute rates. A person makes a total of 12 minutes of ISD calls in a month. If 80% of his ISD bill amount came from calls made to the 'Rest of the World' group, then the ISD calls of the minimum duration were made to which of the following groups of countries?

• A. USA, Canada, Europe (Fixed Line)
• B. Gulf, Europe (Mobile), SAARC
• C. Rest of the world
• D. Cannot be determined

Hint:

Notice that the 80% figure is about bill amount, not minutes, and no per minute rate is given for any group.

Answer 1

The Correct Option is D

Step 1: List what is actually given.
The person makes 12 minutes of ISD calls in total during the month. Of the total ISD bill amount (in rupees), 80% comes from calls made to the 'Rest of the World' group.

Step 2: List what is needed to answer the question.
The question asks which group got the calls of minimum duration, in minutes. To find that, we need the per minute ISD rate charged to each group, plus the exact split of the 12 minutes across the three groups (USA/Canada/Europe Fixed, Gulf/Europe Mobile/SAARC, and Rest of the World).

Step 3: Check if this data is available.
The 80% figure tells us about money, not minutes. A high bill share does not mean a high number of minutes, since Rest of World calls could easily be priced far higher per minute than the other two groups. Without the actual per minute rates for each group, we cannot convert the 80/20 split of the bill amount into a split of the 12 minutes.

Step 4: Try to rule in or rule out each option.
We cannot confirm option 1 or option 2 as the group with minimum duration, because both fit equally well with an unknown rate structure. We also cannot pick option 3, since 'Rest of the World' having 80% of the bill does not force it to have the least time, it could easily have used most of the minutes too if its rate is only slightly higher.

Final Answer:
Since the rates per group and the exact time split are never given, the group with the minimum call duration cannot be found from the data available. \[ \boxed{\text{Cannot be determined}} \]