Question
Two cars start from a place with a speed of 30 km/hr at
an interval of 10 minutes. What is the speed of a man coming from the opposite direction towards the place if he meets the cars at an interval of 6 minutes?Solution
Distance covered in 10 minutes at 30 km/hr = 30 x (10/60) Distance covered in 6 minutes at (30 + x) km/hr = (10/60) x (30 + x) Now, Distance covered in 10 minutes at 30 km/hr = Distance covered in 6 minutes at (30 + x) km/hr ⇒ 30 x (10/60) = (6/60) x (30 + x) ⇒ 30 x 10 = 180 + 6x ⇒ 300 = 180 + 6x ⇒ 6x = 300 - 180 = 120 ⇒ x = 20 km/hr
The element used for making solar cells is
Which of the following is a physical change?
The gas used for filling weather balloons is-
Bronze is an alloy of-
The most reactive among the halogens is-
_________is the process in which acids and bases react to form salts and water.
The acid used in lead storage cells is-
The pH of a neutral solution is —
Which metal is extracted from seawater?
Milk tastes sour when kept in the open for sometimes due to the formation of-