k = 42
given that x and y vary inversely then the equation connecting them is
y = ← k is the constant of variation
to find k use the condition y = 6 when x = 7
k = yx = 6 × 7 = 42
219 / 3,200 = 6.84
1.00 is the price of the battery. since the torch cost 1.50 more than the battery we just subtract what we know is how much more the torch cost from the total cost. while this has no meaning to the question i just wanted to put this in here.
first we divide 1.50 by 2.50 to get it as a decimal. which gives us 0.6. now we put 6/10 then try to simplify it.
3/5 is our answer