Out of the shirts produced in a factory, are defective, while of the rest are sold in the domestic market. If the remaining shirts are left for export, then the number of shirts produced in the factory is
Out of the shirts produced in a factory, are defective, while of the rest are sold in the domestic market. If the remaining shirts are left for export, then the number of shirts produced in the factory is
Solution
We work through this to understand how different percentages relate to each other.
We say the factory produces x shirts in total.
Here's what happens to these shirts:
15% are defective (these can't be sold)
The remaining 85% are good shirts that can be sold
Why 85%? Because if 15% are defective, then 100% - 15% = 85% are good.
Now, from these 85% good shirts:
20% are sold in the domestic market
The remaining 80% are exported
Why 80%? Because if 20% of the good shirts go to domestic market, then 100% - 20% = 80% of the good shirts are exported.
Here's the key insight: We need to find what percentage of the total production goes for export.
The exported shirts = 80% of the good shirts
The good shirts = 85% of total production
So, Exported shirts = 80% of 85% of total production
Converting to decimals: 0.80 × 0.85 = 0.68 = 68%
This means 68% of all shirts produced are exported.
We're told that 8840 shirts are exported.
Since exported shirts = 68% of total production:
68% of x = 8840
Converting percentage to fraction:
$x = \tfrac{8840 × 25}{17}
= \tfrac{221000}{17}
= 13000$
Therefore, the factory produces 13000 shirts.
When dealing with "percentage of percentage" problems, multiply the percentages to find the final percentage of the total.