Secondary School (English Medium) (5 to 8) इयत्ता ८ - CBSE Question Bank Solutions for Mathematics

The cells of a bacteria double itself every hour. How many cells will there be after 8 hours, if initially we start with 1 cell. Express the answer in powers.

Predicting the ones digit, copy and complete this table and answer the questions that follow.

1. Describe patterns you see in the ones digits of the powers.
2. Predict the ones digit in the following:
   1. 4¹²
   2. 9²⁰
   3. 3¹⁷
   4. 5¹⁰⁰
   5. 10⁵⁰⁰
3. Predict the ones digit in the following:
   1. 31¹⁰
   2. 12¹⁰
   3. 17²¹
   4. 29¹⁰ 

Which quantities in the previous question vary inversely with each other?

Which of the following vary inversely with each other?

If two quantities p and q vary inversely with each other, then ______

If xy = 10, then x and y vary ______ with each other.

When two quantities x and y are in ______ proportion or vary ______ they are written as `x  oo  1/y`.

Both x and y are said to vary ______ with each other if for some positive number k, xy = k.

Two quantities are said to vary ______ with each other if an increase in one causes a decrease in the other in such a manner that the product of their corresponding values remains constant.

If 12 pumps can empty a reservoir in 20 hours, then time required by 45 such pumps to empty the same reservoir is ______ hours.

If x varies inversely as y, then 

If on increasing a, b decreases in such a manner that ______ remains ______ and positive, then a and b are said to vary inversely with each other.

If two quantities p and q vary inversely with each other then ______ of their corresponding values remains constant.

If x varies inversely as y and x = 4 when y = 6, then when x = 3 the value of y is ______.

In case of inverse proportion, `a_2/- = b_2/-`

When the speed is kept fixed, time and distance vary inversely with each other.

Length of a side of an equilateral triangle and its perimeter vary inversely with each other.

If d varies directly as t², then we can write dt² = k, where k is some constant.

If a tree 24 m high casts a shadow of 15 m, then the height of a pole that casts a shadow of 6 m under similar conditions is 9.6 m.

If x and y are in inverse proportion, then (x + 1) and (y + 1) are also in inverse proportion.