a wholesaler sells 800 units of socks this month, which represents a 35% increase over last month. what were the units sold last month?

Question

The answer i got is 520 units sold last month 

Answer 1

Let x = number of units sold last month.

 

"800 .. is ... 35% increase over last month"     means

 800    =      x   +  (35/100)x         [note: 35% may be (35/100) or 0.35 as needed by problem]

 

80000 = 100x + 35x           [multiply all by 100 to get rid of fraction]

80000 = 135x               [collect terms]

 592.59 = x                 [divide both sides by 135]

 

Now, be careful !!   Don't simply round x to the nearest whole number (although that usually is close to the right answer).  You should realize that 35% has already been rounded.  So, any of the values 593-596 to 800 is a 35% increase.

    From       To        increase

    593        800         35.36%

    594        800         35.14%

    595        800         34.90%

    596        800         34.68%

Answer 2

Hi Lacaryra,

 

Let the amount he sold last month be 100 units. This month he would have sold 135 units with a 35% increase.

We can now use proportion to find the actual number of units.

for 100 units he sold 135 units

for x units     he sold 800 units

 

cross multiply

800*100 = 135x

x =  593 (rounded to the nearest whole number)

The answer should be 593 units.

 

Answer 3

assume that current month sales is (y) and the previous month sales is (z)

so 

y = 1.35 x z = 800

 

So 

z = 800 / 1.35 = 592.6 ≈ 592 Units