Question

Q.250 cm3(cube) of the liquid weighs 125 grams. find the weight of 1000 cm3(cube) of the liquid.

Q.The cost of a long distance call lasting 20 seconds was 23.40 at this rate what was the cost of a call lasting 6 minutes 30 seconds.

Answer 1

#1
to get this, we just use ratio and proportion.
let x = weight of 1000 cm^3 liquid.
250 cm^3 : 125 g = 1000 cm^3 : x g
thus we can rewrite this as,
250/125 = 1000/x
solving for x,
2 = 1000/x
2x = 1000
x = 500 grams

#2
here, we also use ratio and proportion. first we convert 6 min and 30 seconds to seconds:
6 min = 360 seconds
thus 360 + 30 = 390 seconds
let x = cost of 390 second call
20 : 23.4 = 390 : x
thus,
20/23.4 = 390/x
0.855 = 390/x
x = 390/0.855
x = 456.3

hope this helps~ :)