A student weighed some raisins and recorded the weight as 'x'. She then soaked the raisins in distilled water. After about 2 hours she removed the raisins, wiped them dry and weighed again and recorded that as 'y'. The percentage of water absorbed by raisins may be determined using the relationship; A.; B.; C.; D. (y-x) x 100(All India - 2012)
Answers
NOTE - The omitted options for the question are :
(A) { (y - x) / y } × 100
(B) { (y - x) / x } × 100
(C) { (y - x) / x } × (1 / 100)
(D) (y - x) × 100
The percentage of water absorbed by the raisins may be determined by using the relationship, {(y -x) / x } × 100. Hence, option (B) is correct.
• Weight of dry raisins before soaking in water = x
Weight of raisins after soaking in water = y
• Naturally, the weight of raisins will increase after soaking in water because of the absorption of water by them. Therefore, y > x.
• Now, difference in weight of raisins after and before soaking in water = y - x
• Therefore, percentage of water absorbed by the raisins = (Difference in weight of raisins / Weight of dry raisins ) × 100 %
= { (y - x) / x } × 100 %
∴ { (y - x) / x } × 100 % (option B) is the percentage of water absorbed by the raisins in 2 hours.