Question

A baker ordered 10 kg of premium flour and some additional kg of standard flour. The price of premium flour per kg was twice that of the standard flour. Due to an ordering error, the quantities of the two types of flour were interchanged. This decreased the total cost by 25%. Find the ratio of the quantity of premium flour to standard flour in the original order.

• A. 1 : 2
• B. 5 : 2
• C. 3 : 4
• D. 4 : 5

Answer 1

Answer:

B. 5 : 2

Let the price of standard flour be ₹1 per kg.

Then the price of premium flour = ₹2 per kg.

Original order:

• Premium flour = (10) kg

• Standard flour = (x) kg

  Original cost

$10(2) + x(1) = 20 + x$

Due to interchange:

• Premium flour = (x) kg

• Standard flour = (10) kg

  New cost

$2x + 10$

The new cost decreased by (25%), so:

$2x + 10 = 75\% \text{ of } (20 + x)$
$2x + 10 = \frac{3}{4}(20 + x)$

Multiply by 4:

$8x + 40 = 60 + 3x$
$5x = 20$
$x = 4$

So the original quantities were:

• Premium flour = 10 kg

• Standard flour = 4 kg

Therefore, the ratio is:

$10:4 = 5:2$

So, the required ratio is:

$\boxed{5:2}$