Well, 1/2 is equal to 5/10... so 7/10 - 5/10 is 2/10 because 7-5=2 :)
There are 4 significant figures as the zero is placed between significant numbers.
Answer:
y=6,5,4,3 are value for y
Let,
digital cameras be "x"
video cameras be "y"
Now,
According to the question,
5x + 3y = $3,213..................................................equation (1)
y = 4x..................................................................equation (2)
Taking equation (1)
5x + 3y = $3,213
Substituting the value of "y" from equation (2), we get,
5x + 3(4x) = $3,213
5x + 12x = $3,213
17x = $3,213
x = $3,213 / 17
x = $189
Taking equation (2)
y = 4x
Substituting the value of "x", we get,
y = 4 ($189)
y = $756
Now,
John buys a digital and a video camera. So, it costs him ($189 + $756) = $945
(13 + x)/(50 - x ) = (2/1)
Cross Multiply
2(50-x) = 1(13 + x)
100 - 2x = 13 + x
add 2x to both sides
100 -2x + 2x = 13 + x + 2x
100 = 13 + 3x
Subtract 13 from both sides
100 - 13 = 13 - 13 + 3x
87 = 3x
divide both sides by 3
29 = x
(13 + 29)/(50-29) = 42/21 = 2 to 1 ratio
