Which of the following is linear equation.

A man sets out on a journey. He travelled for a total of 16 hours. He covered the first half of the distance at a speed of 40 km / h and the second half at 60 km / h. What is the total distance he travelled?

A reduction of 20% in the price of sugar enables a housewife to purchase 6 kg. more for Rs. 240. What is the original price per kg. of sugar?

The angle of elevation of the top of a tower from a point A on the ground is 30^o. On moving a distance of 20 m towards the foot of the tower to a point B, the angle of elevation increase to 60^o.The height of the tower is-

Find the least number which when divided by 12, 15, 18 and 27 leaves remainders 10, 13, 16 and 25 respectively.

If "basis points" are defined so that 1 percent is equal to 100 basis points, then by how many basis points is 82.5 percent greater than 62.5 percent. 

State Electricity Board gives a discount of 15% if the electricity bill is paid before the due date. If a person gets a discount of Rs 54, then what was the original bill amount?

The top of two poles of height 24m and 36 m are connected by a wire. If the wire makes an angle of 60° with the horizontal, then the length of the wire is