Answer:
1365 rupees
Step-by-step explanation:
1. Approach
The easiest method to solve this problem is via the method of proportions. One can use a proportion to find the original price of the watch. Then one can find the price of the watch if the watch had a (30%) mark up, by using a proportion.
2. Find the original price
Remember, the general format of a proportion is the following:
[tex]\frac{part}{total}=\frac{percent}{100}[/tex]
The following information is given:
The watch sold for (1260) rupees which is (120%) of the original price. Remember, there was a (20%) gain, meaning that the seller recovered (120%) of the price, in essence, the price of the watch, plus (20%) extra, thus (120%). Substitute these values into the proportion and solve,
[tex]\frac{part}{total}=\frac{percent}{100}[/tex]
[tex]\frac{1260}{total}=\frac{120}{100}[/tex]
Simplify,
[tex]\frac{1260}{total}=\frac{120}{100}[/tex]
[tex]\frac{1260}{total}=\frac{6}{5}[/tex]
Cross product,
[tex]\frac{1260}{total}=\frac{6}{5}[/tex]
[tex](5)(1260)=(6)(total)[/tex]
Simplify,
[tex](5)(1260)=(6)(total)[/tex]
[tex]6300=6*total[/tex]
Inverse operations,
[tex]6300=6*total[/tex]
[tex]1050=total[/tex]
3. Find the price if the mark up is (30%)
Now, one knows the original price of the watch. Set up a proportion to find the price of the watch if there is a (30%) mark up. Use the same logic to set up this proportion as was used to set up the last one. The (percent) will be (130%) because the new price of the watch is (130%) of the original watch.
[tex]\frac{part}{total}=\frac{percent}{100}[/tex]
Substitute,
[tex]\frac{part}{total}=\frac{percent}{100}[/tex]
[tex]\frac{part}{1050}=\frac{130}{100}[/tex]
Simplify,
[tex]\frac{part}{1050}=\frac{130}{100}[/tex]
[tex]\frac{part}{1050}=\frac{13}{10}[/tex]
Cross products,
[tex]\frac{part}{1050}=\frac{13}{10}[/tex]
[tex](10)(part)=(13)(1050)[/tex]
Simplify,
[tex](10)(part)=(13)(1050)[/tex]
[tex]10*part=13650[/tex]
Inverse operations,
[tex]10*part=13650[/tex]
[tex]part=1365[/tex]
Thus, the price after the (30%) is (1365) rupees.
