Answer:
a) Original price= $420000
b) Saving= $ 42000.
Explanation:
Given: Purchase price of beach house= $378000
Price reduction= 10%
Let the original price be `x`
Now, computing to find the value of original price.
Purchase price=
![Original\ price- Original\ price* discount\%](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zn5wwv4nhtxpefgbfmosw78gsptz7nrys9.png)
⇒
![\$ 378000= x-x* 0.10](https://img.qammunity.org/2020/formulas/mathematics/middle-school/jal29oqo144s2ek369n9rvv0zpey5ij2qo.png)
⇒
![\$ 378000= x-0.10x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/92y5tv3k4x557ndqifqwi5a0009n47x7ze.png)
⇒
![\$ 378000= 0.9x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/kjvyhxqjnwjst6zzh53v1v9lplrt6t4iy2.png)
Cross multiplying both side
∴ x=
![(378000)/(0.9)= \$ 420000](https://img.qammunity.org/2020/formulas/mathematics/middle-school/y2xa2kj7euk5mrvpqjo2c99j517dzagb2k.png)
∴ Original price= $420000.
Saving= Original price - Purchase price
Saving=
![\$ 420000-\$ 378000= \$ 42000](https://img.qammunity.org/2020/formulas/mathematics/middle-school/a5n4ojt5k48d9fnl4mbnit9uli0gypujr8.png)
∴ Saving made by Mark and David is $42000.