80. Two metal rods, 1 & 2 of same length have same 8 temperature difference between their ends, their
thermal conductivities are K, & K, and cross
sectional areas A, & A, respectively. What is
required condition for same rate of heat conduction
in them.
(1) K1= K2
(2) K1 A, - K2 A,
(3) K1/A1=K2/A2
(4)K1/l1^2=K2/l2^2
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step-by-step explanation:

mr. flanders’ class sold 47 doughnuts and   mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations: