The temperature of the furnace is 1200 and cool at a rate of 15 per minute the temperature of another furnace is 900 and is heat at a rate of 5 per minutes after how many minutes will the furnace be at the same temperature

After 15 minutes, the temperature of both the furnaces will be same.

Step-by-step explanation:

Let be the minutes when the temperature of both becomes same.

Now, as per question:

Temperature of the furnace after minutes that is cooling at the rate of 15 degree per minute is given as:

Temperature of the furnace after minutes that is heating at the rate of 5 degree per minute is given as:

Now, equating both the temperatures, we get

Therefore, after 15 minutes, the temperature of both the furnaces will be same.

(d)

step-by-step explanation:

given: the line in the graph passes through points (5,30) and (6,26).

then, the equation of line is:

now, put y=a(n) and x=n,

hence, option d is correct.