Question 174786
First, what are the equations that describe the situation:

Let x be the amount invested in the first venture.

Let Y be the amount invested in the second venture.

So x + y = 25000 (#1) (I'll disregard including the "P" for pounds in the intermediate steps of my calculation)

.15x -.05y = .08*25000 (#2)(This equation describes the relationship between th ereturn on each of the two ventures and the return on the total amount invested.

.15x - .05 (25000 - x) = 2000 (Substituting for "y" based on equation  #1)     performing the multiplication

Simplify  

.15x - 1250 +.05x = 2000
Rearrange the equation

.2x = 2000+1250 = 3250

So x = 3250/.2 = P16250

From equation #1, solve for y

y = 25000 - 16260 =P8750

Checking the results by substituting the answers into the equations

16250 + 8750 = 25000 (OK)

.15*16250 -.05*8750 = 2437.5 - 437.5 = 2000

25000*.08 = 2000 (OK)