(i) Irfan says that he has 7 marbles more than five times the marbles Parmit has.

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. (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 bey 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, die vertex angle is twice either base angle. (Let the base angle be A in degrees. Remember that the sum of angles of a triangle is 180 degrees).

Answer 1

(i)  Let the number of marbles Parmit had be ‘m’
∴ Number of marbles Irfan has = Five times of parmits marble 5m.
To this 7 marbles more means = 5m + 7
∴ 5m + 7 = 37.

(ii) Let the age of Lakshmi be ‘y’ years
Three times of age = 3y
More than 4 years = 3y + 4
∴ Lakshmi’s father age be = 3y + 4
∴ 3y + 4 = 49

(iii)  Let the lowest score be ‘l’
Twice the lowest score be = 2l
Plus seven = 2l + 1
∴ The highest score = 2l + 7
∴ 2l + 7 = 87

(iv) Let the base angle be b°
Vertex angle = Twice the base angle
∴ Vertex angle = 2b
Sum of the angles of an isosceles triangle is =180°
∴ 2b + b + b = 180° = 4b = 180°