Based on the hands on card “ OLS in Python Statsmodels” What is the adjusted R sq value ?

When a certain potentiometer is used to measure an unknown emf, the standard emf has a value of 1.2076 V . When the standard emf is in the circuit and resistances R_1 and R_2 are adjusted so that no current flows through the galvanometer, the values of R_1 and R_2 are 2.42 Omega and 4.84 Omega , respectively. When the unknown emf is in the circuit, the value of R_2 is 3.66 Omega . What is the value of the unknown emf ?

A tank with rectangular base and rectangular sides,open at the top is to be constructed so that its depth is 2m and volume is 8m3. If building of tank casts Rs.70 per sq.metre for the base and Rs.45 per sq.metre for sides, what is the cost of least expensive tank?