A digital camera memory card is 1/4 full. The card is 2/3 full when 375 more pictures have been taken.

A) How many pictures can the memory card hold??

B) How many pictures were originally on the memory card??



Answer :

To get the answer first we have to find full numbers.
We can use proportion
2/3 ----------------------- 375
1 -------------------------- x
Crossmultiply now
2/3*x=375           /:2/3 
x=[tex]375: \frac{2}{3} [/tex] 
x=[tex]375* \frac{3}{2}=562 [/tex] - its the answer A)
Now we have to find how much were originally on the card.
To get the answer we can just multiply 562 times 1/4.
562*1/4=140 - its the asnwer B)

Let

x--------> total of images that the memory card can contain


we know that

[tex] \frac{2}{3} x=\frac{1}{4} x+375 [/tex]

Multiply by [tex] 12 [/tex] both sides

[tex] 8x=3x+375*12\\ 8x-3x=4,500\\ 5x=4,500\\ x=900 pictures [/tex]


originally on the memory card

[tex] \frac{1}{4} x\\ =\frac{1}{4} *900\\ =225 pictures [/tex]

therefore


the answer part a) is

[tex] 900 pictures [/tex]


the answer part b) is

[tex] 225 pictures [/tex]