Question

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. (Tale 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 are 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°. )

Answer 1

(i)Let m be the number of Parmit’s marbles. 

\5m + 7 = 37 

(ii) Let the age of Laxmi be y years. 

\3 y + 4 = 49 

(iii) Let the lowest score be l. 

\2l + 7 = 87 

(iv) Let the base angle of the isosceles triangle be b, so vertex angle = 2b. 

\2b + b + b = 180° 

⇒ 4b = 180° [Angle sum property of a trangle ]