The boiling & freezing points on a newly defined temperature scale in degree 'D' are 400°D & 100°D respectively. The temperature reading corresponding to 60°C on this new temperature scale will be equal to __________ °D.

ANS:D - 280

Check the accuracy of result by computing the equivalent of °D at 0°C.

1. 400°D = 100°C.
X°D. =. 0°C.

(400-100)°D/(100-0)°C=3°D/1°C.
General formula:
(400 - °D)/(100 - °C)=3/1.

(400 - °D) = 3x (100 - °C),
°D = 400 - 3 x (100 - °C),

So for 60°C
°D = 400 - 3 x (100 - 60),
°D = 400 - 3 x (40),
°D = 400 - 120,

°D = 280.

If 0°C
°D = 400 - 3 x (100 - 0),
°D = 400 - 3 x (100),
°D = 400 - 300,
°D = 100°D.