Question
The average of 16 numbers is 20. The average of 1st 7
numbers is 15 and the average of the last 7 numbers is 25. The 8th number is 16 more than the 9th number. What is the value of the 8th and 9th numbers?Solution
Let the 8th and 9th numbers be x and y respectively. Sum of 16 number = 16 × 20 = 320 Sum of first 7 number = 7 × 15 = 105 Sum of last 7 number = 7 × 25 = 175 ATQ: x + y = 320 - 105 - 175 x + y = 40 We know that: x = 16 + y so, 16 + y + y = 40 2y = 40 - 16 = 24 y = 12 then, x = 16 + 12 = 28
A pond of water appears less deep due to –
Which law states that the ratio of the potential difference across a conductor to the current through it is constant, provided the temperature remains c...
When white light passes through a glass prism, which color deviates the least?
The weight (W) of a body is derived from which formula?
What is the momentum of a 2 kg object moving at 3 m/s?
In an experimental arrangement of a Fresnel's biprism, monochromatic light of wavelength 2. is used to produce interference fringe pattern. On introduc...
Parsec is the unit of
Match the following machines with their working principles:
(i) Electric motor - (a) Heat energy into mechanical energy
(ii) Steam engin...
What happens to the electrostatic force between two charges when the distance between them decreases?
Relevant for Exams:
