If Mary and Tom put their money together they have £36. If Mary's money were halved and Tom's money doubled they would have £42. How much does each of them have? If you're answering, could you please show working out, thanks so much.

Mary: £20

Tom: £16

Step-by-step explanation:

Let x=the number of £ Mary has and y=number of £ Tom has.

x+y=36  ==>x=36-y

x/2+2y=42 ==> x+4y=84

36-y+4y=84

36+3y=84

3y=48

y=16

x+y=36, so x+16=36, so x=20

-13

step-by-step explanation:

f(x)=2x-5 for f(-4)

f(-4)   means let x=-4

f(-4) = 2(-4) -5

f(-4) =-8-5

      = -13

the equation cos(35) =a/25 can be used to find the length of bc what is the length of bc? round to the nearest tenth

step-by-step explanation: