Q. 85.0( 2 Votes )

# A school has 630 students. The ratio of number of boys to number of girls is 3:2. This ratio changes to 7:5 after the admission of 90 new students. Find newly admitted boys.

Answer :

New ratio = 7:5

Let ratio be x

Number of boys = 7x

Number of girls = 5x

Total students = 630 + 90 = 720

Total students = Number of boys + Number of girls

720 = 7x + 5x

720 = 12x

x = 60

Number of boys = 7x

= 60×7

= 420

Rate this question :

Express y in terms of x, given that Check whether ( – 5, 2) is a solution of the given equation.

RS Aggarwal & V Aggarwal - MathematicsWrite two solutions for each of the following equations:

(i) 3*x*+4*y* =7

(ii) *x*=6*y*

(iii) *x*+π*y* =4

(iv) *x*-*y* =4

How many linear equations are satisfied by *x*=2 and *y*=-3?

If (2*k*-1,*k*) is a solution of the equation 10*x*-9*y*=12, then *k*=

If (*a*,4) lies on the graph of 3*x*+*y*=10, then the value of *a* is

Show that (3, 1) as well as (2, – 2) are the solutions of the equation 3x – y = 8. Find two more solutions. How many solutions can we find?

RS Aggarwal & V Aggarwal - MathematicsIf each of ( – 2, 2), (0, 0) and (2, – 2) is a solution of a linear equation in x and y, then the equation is

RS Aggarwal & V Aggarwal - Mathematics