Shikha painted `1/5` of the wall space in her room. Her brother Ravish helped and painted `3/5` of the wall space. How much did they paint together? How much the room is left unpainted?

Simran painted 2/3 of the wall space in her room. Her brother Rahul helped and painted 1/5 of the wall space. How much did they paint together?

Shubham painted 2/3 of the wall space in his room. His sister Madhavi helped and painted 1/3 of the wall space. How much did they paint together?

Shubham painted 2/3 of the wall space in his room. His sister Madhavi helped and painted 1/3 of the wall space. How much did they paint together?

Jagya cleaned 1/(7) of the school playground while his friends Bashir and Hazel cleaned 2/(7) and 3/(7) of the playground, respectively. How much did they clean together? What portion of the playground is yet to be cleaned?

Reema and Pooja ordered a medium pizza each. Reema finished 5/(8) of her pizza and Pooja finished 7/(8) of hers. How much pizza did they finish together?

Anjali had read (2)/(3) of the book when she sat in her school bus. (1)/(4) of the book was left when she got off from the bus. How much did she read in the bus?

Anil had to paint a wall. He painted 25% of the wall. Umar came and painted 30 sq. m of the wall. If 60% of the wall is left unpainted, how many square metres of wall did Anit paint?

Asha bought 3(1)/(4) m of cloth and Mrinal bought 2(2)/(5) m of cloth. How much cloth did they buy together?

Imagine a system, that can keep the room temperature within a narrow range between 20^@C to 25^@C . The system includes a heat engine operating with variable power P = 3KT, where K is a constant coefficient, depending upon the thermal insulation of the room, the area of the walls and the thickness of the walls. T is temperature of the room in temperature drops lower than 20^@C , the engine turns on, when the temperature increase over 25^@ C, the engine turns off, room looses energy at a rate of K(T - T_0), T_0 is the outdoor temperature. The heat capacity of the room is C. Given (T_0=10^@C, ln(3/2) =0.4 , ln(6/5)=0.18 , C/K =750 SI-unit) Suppose at t = 0, the engine turns off, after how much time interval, again, the engine will turn on

Imagine a system, that can keep the room temperature within a narrow range between 20^@C to 25^@C . The system includes a heat engine operating with variable power P = 3KT, where K is a constant coefficient, depending upon the thermal insulation of the room, the area of the walls and the thickness of the walls. T is temperature of the room in temperature drops lower than 20^@C , the engine turns on, when the temperature increase over 25^@ C, the engine turns off, room looses energy at a rate of K(T - T_0), T_0 is the outdoor temperature. The heat capacity of the room is C. Given (T_0=10^@C, ln(3/2) =0.4 , ln(6/5)=0.18 , C/K =750 SI-unit) Suppose at t = 0, the engine turns on, after how much time interval again, the engine will turn off