Daniel bought a desk which regularly costs $250. It is on sale that is 15% off.
In decimal 15% = 15/100 = 0.15
So after sale the selling price is $ (250 ×(1-0.15))
Also x% sales tax applied to it.
After including sales tax, the price is $(250 ×(1-0.15)) + $ (250 ×(1-0.15)×(x/100))
Now here $(250×(1-0.15) is common to both of them. If we take it out we will get $(250×(1-0.15)×(1+x/100))
So Daniel pays $(250×(1-0.15)×(1+x/100)) for a desk.
Daniel also bought a desk chair whose regular selling price is $145. There is 15% off.
So the price will be $(145 ×(1-0.15))
There is also x% sales tax. So after sales tax Daniel pays
$(145×(1-0.15)) + $(145×(1-0.15)×(x/100)
= $(145×(1-0.15)×(1+x/100))
So the total amount Daniel pays
$(250×(1-0.15)×(1+x/100)) + $(145×(1-0.15)×(1+x/100))
We can take out (1-0.15)×(1+x/100)
$(250+145)×(1-0.15)×(1+x/100) = $(250+145)×(1-0.15)×(100/100 + x/100)
=$(250+145)×(1-0.15)×((100+x)/100)
This is option D. So option D is correct.
$(250+145)×(1-0.15)×(1+x/100)
$395×(0.85)×(1+x/100)
$395×(0.85 + 0.85x/100)
$395×(0.85 + 0.0085x)
$395(0.85) + $395 (0.0085x)
This is option A. So option A is also correct.
We will not get option B and C. So we can say option B and C do not represent the amount that Daniel pays.
