Answer:
The number of pens sold on Monday is 107 pens
Step-by-step explanation:
total pack of pen sold by the retailer in 3 days = 10 packs
total number of pens in the 10 packs = 48 x 10 = 480 pens
let the number of pens sold on Monday = x
let the number of pens sold on Sunday = y
let the number of pens sold on Tuesday = z
He sold twice as many pens on Sunday than on Monday
y = 2x ------equation (1)
He sold 55 pens fewer on Tuesday than on Sunday
y = z + 55 ------equation (2)
total number of pens sold in the three days
y + z + x = 480 ------equation (3)
from equation (1) make x the subject of the formula
x = y/2
from equation (2) make z the subject of the formula
z = y - 55
substitute the value of x, and z into equation (3)
y + y/2 + y - 55 = 480
2y + y/2 = 480 + 55
5y/2 = 535
5y = 535 x 2
5y = 1070
y = 1070 / 5
y = 214
The number of pens sold on Monday is:
x = y / 2
x = 214 / 2
x = 107 pens
Thus, the number of pens sold on Monday is 107 pens
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