A ruler cost Y kobo, an eraser is 5 kobo less than thrice the ruler.Find the cost if the ruler and eraser.

Answer 1

r = Y
e = 3 r - 5
or
e = 3 Y - 5
You better know Y

Answer 2

Ruler cost Y kobo.
Eraser cost 3y - 5 kobo.
Total cost = y + 3y-5 = 4y-5.