The first number is 80% of the second, the second is 40% of the third, and the third is 20%

The first number is 80% of the second, the second is 40% of the third, and the third is 20% of the fourth. Find these numbers if their sum is 336. What is the lower number.

1. If we designate the fourth number “X”, then the third number will be X * 20%, that is, “0.2X”.

2. Let us express the second number, which is 40% of the third:

(0.2X) * 40% = 0.2X * 0.4 = 0.08X.

3. It remains to express the first number, which is 80% of the second:

(0.08X) * 80% = 0.08X * 0.8 = 0.064X.

4. Adding all the expressions of our numbers, we get 336. Let’s compose and solve the equation:

X + 0.2X + 0.08X + 0.064X = 336;

1.344X = 336;

X = 336 / 1.344;

X = 250 is the IV number.

5. Find all the other numbers:

250 * 0.2 = 50 – III number;

50 * 0.4 = 20 – II;

20 * 0.8 = 16 – I.

The first number, whose value is 16, is the smallest.