Solve the following:
$(a)$ The teacher tells the class that the highest marks obtained by a student in her class is twice the lowest marks plus 7. The highest score is 87. What is the lowest score?
$(b)$ In an isosceles triangle, the base angles are equal. The vertex angle is 40°. What are the base angles of the triangle? [Remember, the sum of three angles of a triangle is $180^{\circ}$].
$(c)$ Sachin scored twice as many runs as Rahul. Together, their runs fell two short of a double century. How many runs did each one score?

AcademicMathematicsNCERTClass 7

To do:

We have to solve the given questions.


(a) Highest score $=87$.

Let the lowest marks be $x$

According to question,

Highest marks obtained $= 2\times x+7$






(b) Let one of the base angles be $b$. Since the triangle is isosceles, the other base angle will also be $b$.

Vertex angle $=40^{\circ}$.

The sum of the three angles of a triangle$=180^{\circ}$







(c) Let Rahul's score be $x$.

This implies,

Score of Sachin $=2\times x$


According to question,

$x+2x=198$                                      [1 century$=100$, thus, double century$=200$]




So, Rahul’s score $=66$ runs

And Sachin’s score$=2x$


$=132$ runs

Updated on 10-Oct-2022 13:33:38