Finding the Unknown Class 7 Long Question Answer

Finding the Unknown Class 7 Long Question Answer

Finding the Unknown Class 7 Long Question Answer

Question 1.

People of Sundargram planted trees in the village garden. Some of the trees were fruit trees. The number of non-fruit trees were two more than three times the number of fruit trees. What was the number of fruit trees planted if the number of non-fruit trees planted was 77 ?

Solution:

Let the number of fruit trees planted by the people of Sundargram be x.

and the number of non-fruit trees planted would be x × 3 + 2 = 3x + 2.

3x + 2 = 77.

3x + 2 - 2 = 77 - 2

or 3x - 75

or [latex]\frac {3x}{3}[/latex] = [latex]\frac {75}{3}[/latex] or x = 25.

So, the number of fruit trees planted was 25.

Question 2.

Solve the following riddle :

I am a number,

Tell my identity ! Take me seven times over

And add a fifty !

To reach a triple century

You still need forty !

Solution:

Let the number be x.

According to the question,

7x + 50 = 3 × 100 - 40

∴ 7x + 50 = 300 - 40.

or 7x + 50 - 50 = 300 - 40 - 50

or 7x = 210

or [latex]\frac {7x}{7}[/latex] = [latex]\frac {210}{7}[/latex]

or x = 30.

Thus, your identity is 30.