write an expression in terms of x, to represent the total number of prson buying jewlery or cosmetics or both?

Question

a department store sells jewellery and cosmetics. On a certain day the total number of persons buying jewellery or cosmetics or both was 400. given that 250 persons bought jewellery, 2x persons bought cosmetics only, x persons bought both jewellery and cosmetics.
(a) write an expression in terms of x, to represent the total number of person buying jewlery or cosmetics or both

Answer 1

J = number of persons purchasing only jewelry
C = number of persons purchasing only cosmetics
B = number of persons purchasing both

"On a certain day the total number of persons buying jewellery or cosmetics or both was 400."

J + C + B = 400

"250 persons bought jewellery..."

J = 250

"2x persons bought cosmetics only..."

C = 2X

"x persons bought both jewellery and cosmetics."

B = X

Now substitute these into the first equation

J + C + B = 400

( 250 ) + ( 2 X ) + X = 400

This simplifies to

3 X = 150

X = ( 1 / 3 ) ( 150 )

X = 50

Answer 2

If she has n nickels and 25 funds in entire, meaning she has 25 - n dimes. each and every nickel is nicely worth 5 cents, needless to say, and each dime is nicely worth 10 cents. So the entire value could be: 5 * n + 10 * (25 - n) = 5n + 250 - 10n = 250 - 5n