Pens come in package of 10. Eraser come in package of 12. Jane want to purchase the
smallest number of pen and eraser, so she will exactly 1 eraser per pen. How many packages of pen and eraser should she buy?
x packages of erasers
y packages of pens
number of erasers = 12x
number of pens = 10y
but 12x = 10y
x/y = 10/12
x : y = 10 : 12 = 5 : 6 in lowest term ratios
so 5 packages of erasers and 6 packages of pens