A shopper spends $25 to purchase floppy disks at 50¢ each. The next

First day he bought 25/0.5= 50 disk

Second day he bought 45/0.3= 150 disk

average price per disk = (70/ 200) = 7/20

for easy calculation 7/20 = 7/10 * 1/2 = 0.7 * 0.5 =0.35

Answer: C

It seems this is an old question since floppy dist era

A shopper spends $25 to purchase floppy disks at 50¢ each. The next day, the disks go on sale for 30¢ each and the shopper spends $45 to purchase more disks. What was the average price per disk purchased?

Shopper spend $25 for floppy disks. Let the number of disks be X.
[Convert to same unit. (100 cents = 1 dollar)]
$25 = 2500 cents.
1 disk for 50 cents = \(\frac{1}{50}\)
Number of disks for 2500 cents = \(\frac{X}{2500}\)
Equating both equations;
\(\frac{1}{50}\) = \(\frac{X}{2500}\)
X = \(\frac{2500}{50}\) = 50 Disks

Disk go on sale for 30 cents.
Shopper spent $45 to purchase more disks. Let the extra number of disks be Y.
$45 = 4500 cents.
1 disk for 30 cents = \(\frac{1}{30}\)
Number of disks for 4500 cents = \(\frac{Y}{4500}\)
Equating both equations;
\(\frac{1}{30}\) = \(\frac{Y}{4500}\)
Y = \(\frac{4500}{30}\) = 150 Disks

Therefore Total number of Disks purchased = X + Y = 50 + 150 = 200 Disks
Total price payed for disks = 2500 + 4500 = 7000 cents.

Average price per disk = Total Price / Total number = \(\frac{7000}{200}\) = 35 cents.
Answer C...

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On Day 1, the shopper spends 25$ to purchase 50 disks
On Day 2 , he will purchase 150 disks at 30¢ each.

Average price per disk = 7000¢/200 = 35¢
Ans C

Since the shopper spent $25, or 2500¢, on the 50¢ disks, he purchased 2500/50 = 50 disks. On the second day, the shopper spent $45, or 4500¢, on the 30¢ disks, and thus he purchased 4500/30 = 150 disks.

Thus, the average price per disk is (2500 + 4500)/(50 + 150) = 7000/200 = 35 cents.

Answer: C

Theory

➡ Average = Sum of all the Values / Total Number of Values
➡ Sum of All the values = Average * Total Number of Values

A shopper spends $25 to purchase floppy disks at 50¢ ($0.5) each

Total Price Paid on First Day = $25
Total Disks Purchased on First Day = Total Price Paid / Price of each disk = \(\frac{25}{0.5}\) = \(\frac{250}{5}\) = 50

The next day, the disks go on sale for 30¢($0.3) each and the shopper spends $45 to purchase more disks

Total Price Paid on Second Day = $45
Total Disks Purchased on Second Day = Total Price Paid / Price of each disk = \(\frac{45}{0.3}\) = \(\frac{450}{3}\) = 150

The average price per disk purchased

Average = Sum of all the Values / Total Number of Values = Total Price Paid in both the days / Total number of disks purchased = \(\frac{25 + 45}{ 50 + 150}\) = \(\frac{70}{200}\) = $0.35 = 35¢

So, Answer will be C.
Hope it helps!

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