A person clapped his hands near a cliff and heard echo after 6 s. The distance of the cliff from the personis: [take v = 346 m/s]

In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No Error'.
 
1. Cybercrime cases pose various kinds of
2. Challenges which requires strengthening of
3. The institutional mechanism.
4. No error

You are given a question and two statements. Identify which of the statements is/are sufficient to answer the question.

Question:

What is the total age of the sisters 10 years from now?

Statements:

1. Lina is 20 years old now.

2. Lina's sister's age is twice that of the age of Lina.

Consider the given arguments as true and decide which of the given assumptions is/are implicit.

Argument :
The best bus travels company has decided to increase its fare by 10%.

Conclusions :
1. Passengers may opt for other buses costing less than the best bus travels company.
2. The demand for the buses by passengers may remain unchanged even after the fare hike.

The given data shows the registration of bikes and total vehicles (in thousands) for 6 months in 2017 in City X.

Note : In the chart, the first number represents bikes and the second number represents total vehicles.

Based on the given data, from January to April 2017, the increase in the registration of vehicles other than bikes is ___.

In a computer game, a builder can build a wall in ten hours while a destroyer can demolish such a wall completely in fourteen hours. Both, the builder and the destroyer were initially set to work together on level ground. But after 7 hours the destroyer was taken out. What was the total time (in hrs) taken to build the wall ?

Consider the given question as true and decide which of the given statements is sufficient to answer the question.
Who among P, Q, R, S and T is lightest in weight?

Statements :
1. Q weight < P and S also S weight > T
2. R weight > Q but < T

Elements A, B and C occur as Dobereiners triads. If the atomic mass of A is 7 and that of C is 39, what will be the atomic mass of B?