cake wghs 550g & has 3 ing. flour sugar & raisins Theres twice as much flour as sugar & one & a half times as much sugar as raisinsthis problem is...

The total weight of the cake is 550g. Let the weight of
raisins be R.

As the cake has one and a half as much sugar
as raisins, the weight of sugar is (3/2)*R

Now as the cake
has twice as much flour as sugar, and the weight of sugar has already been expressed as
(3/2)*R,  the weight of flour is 2*(3/2)*R = 3*R

So the sum
of all the three is 550

=> R + (3/2)*R + 3*R =
550

=> R (1 + 3/2 + 3) =
550

=> R ( 11/2 ) =
550

=> R = 550/
(11/2)

=> R = 1100/11 = 100
g

So the weight of flour in the cake is 3*100
= 300g