Answer:
(1) The required ratio of spirit to varnish is 1:3.
(2) You need 80 ml of mineral spirit.
(3) The ratio of tapestries' heights to width is 3:2.
Step-by-step explanation:
(1) If you need to mix 25% mineral spirit to the varnish, then the solution would contain 25% mineral spirit and 75% varnish.
So,
Thus, The required ratio of spirit to varnish is 1:3.
(2) If you use 240ml of varnish, then this quantity is 75% of the total solution or ration of varnish to the total solution will be 3:4.
Let be the quantity of total solution.
Then, .
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That is, total solution is 320 ml.
Now, Spirit = Total solution - Varnish
⇒Spirit = 320ml-240ml
⇒Spirit = 80ml
Hence, if you use 240 ml of varnish, you need 80 ml of mineral spirit.
(3) Robison's tapestries all measure 1.5m long and 1m wide. First, we express dimensions in whole numbers by multiplying them by 10.
Then, dimensions are 15m long and 10m wide.
Now, Height : Width = 15:10
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Hence, the ratio of tapestries' heights to width is 3:2.