Answer: Hours by Tina practiced this month is 3 times the hours she practiced last month such that 15 x 3 =45 hours.
Step-by-step explanation:
Given : Duration of Tina practiced piano last month= 15 hours
Duration of Tina practiced piano this month= 45 hours
We can see 45 is a multiple of 15 such that 
Therefore, Hours by Tina practiced this month is 3 times the hours she practiced last month such that 15 x 3= 45 hours.
To start with, 76 is 80% of 95. (76/95=0.8)
This means that we take the difference from 100% of 95 and 80% of 95, and get a 20% decrease.
Here's a diagram showing how to combine angles LDA (in red) and angle ADE (in blue). Hopefully it becomes a bit clearer why these two angles add up to line segment LE. Erase the shared segment DA if it helps show LE better.
See attached image below.
You need do like 25$--------100% of real price
x$---------70%
25x70=100<u>x</u>
1,750=100<u>x</u>
<u> x</u>=1750<u />divided by 100=17.5$