# 6.  Set up an equation in the following cases: (i) Irfan says that he has 7 marbles more than five times the marbles Parmit has. Irfan has 37 marbles. (Take m to be the number of Parmit’s marbles.) (ii) Laxmi’s father is 49 years old. He is 4 years older than three times Laxmi’s age. (Take Laxmi’s age to be y years.) (iii) 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. (Take the lowest score to be l.) (iv) In an isosceles triangle, the vertex angle is twice either base angle. (Let the base angle be b in degrees. Remember that the sum of angles of a triangle is 180 degrees).

D Devendra Khairwa

(a) Let the Parmit's marbles be m.

Then according to question we have :     $5m\ +\ 7\ =\ 37$

or                                                                            $5m\ =\ 30$

(b)  Let the age of Laxmi be y years.

Then we have :                              $3y\ +\ 4\ =\ 49$

or                                                               $3y\ =\ 45$

(c)  Let the lowest marks be l, then :

$2l \ +\ 7\ =\ 87$

or                                                              $2l \ =\ 80$

(d)  Let the base angle of the triangle be b degree.

Then according to question we have :

$b\ +\ b\ +\ 2b\ =\ 180^{\circ}$

or                                                                                    $3b\ =\ 180^{\circ}$

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