Question

postcard costing 15 paise each and inland letters costing 75 Paisa each were purchased for Rs 33 total number of postcard and Inland Letter purchased was 60 if the number of postcard and inland letters are interchanged find the cost

Answer 1

let the number of postcards be x

and number of inland letter = y

according to first condition ,

15x + 75y = 3300

x+5y = 220 -------(1)

according to Second condition ,

x+y = 60 ------(2)

subtracting eq 2 from eq 1 we get

4y = 160

y = 40

putting this value in eq 1 we get


x + 5 × 40 = 220

x = 20

i.e. 20 × 0.15 + 40 × 0.75 = 33

now by interchanging values ,


= 40 × 0.15 + 20 × 0.75

= 6 + 15

= 21 rs