Answer:
897.6
Explanation:
Lets put in in equations.
Call X the full capacity of the camera in number of photos. So, when it is 1/4 full it has (1/4)X photos. Lets say that 1/4 full is a number A of photos, so:
(1/4)X = A
Then, you took 374 additional photos and it got 2/3 full. It is, you got, in total, (2/3)X photos, that we will call B photos.
(2/3)X = B
But, we also know that this (2/3)X photos is the sum of the previous (1/4)X photos (or A) plus some other 374 photos. So:
(2/3)X = (1/4)X + 374
As we have one term with X in each side, we woul like to pass all the X's to one only side. For this, sum -(1/4)X in both sides:
(2/3)X - (1/4)X = (1/4)X + 374 - (1/4)X
Operating with fractions:
(8/12)X - (3/12) X = 374
(5/12) X = 374
Multiplying both sides by (12/5) [or dividing by 5/12] to eliminate the (5/12):
X = 374 (12/5)
X = 897.6
The full capacity is 897.6 photos and when the camera was 1/4 full it had 224.4 photos.
You can verify by doing 224.2 + 374 = 598.4 and (2/3)*897.6=598.4