Answer:
Fiona gets 25 sweets
Explanation:
System of Equations
Paul, Fiona, and Pip have some sweets in the ratio 4:5:1. Let's call x,y, and z the number of sweets they have respectively.
The ratios can be written as three separate equations:
![(x)/(y)=(4)/(5)\qquad\qquad[1]](https://img.qammunity.org/2022/formulas/mathematics/high-school/9rjy6abw6pl75tm48cd54tluwzf7eaaon5.png)
![(y)/(z)=(5)/(1)\qquad\qquad[2]](https://img.qammunity.org/2022/formulas/mathematics/high-school/j9n9edkmfaxa7qs4xy9oo6ko1su7n8g76a.png)
![(x)/(z)=(4)/(1)\qquad\qquad[3]](https://img.qammunity.org/2022/formulas/mathematics/high-school/vt1skf9xwlu9y18sdk172954jc793jto1p.png)
Paul has 15 more sweets than Pip, then:
x = z + 15 [4]
Multiplying [3] by z:
x = 4z
Substituing in [4]
4z = z + 15
Subtracting z:
3z = 15
z = 15/3 = 5
Multiplying [2] by z:
y = 5z = 5*5 = 25
Fiona gets 25 sweets