Mason is mixing up some salad dressing. He takes a bowl that holds 150 ml and fills it 2/3rds with oil and 1/3rd with vinegar. The oil weighs 5 g/ml and the vinegar weighs 4 g/ml. How many grams does the salad dressing weigh?
First find how many ml of oil Mason adds by multiplying the volume of the bowl by the proportion filled with oil: 150 ml * 2/3 = 
<gadget id="calculator">150*2/3</gadget>
<output>100</output>
100 ml.
Then repeat the process to find how many ml of vinegar he added: 150 ml * 1/3 = 
<gadget id="calculator">150*1/3</gadget>
<output>50</output>
50 ml.
Now find the weight of the oil by multiplying the volume by the weight/volume ratio: 100 ml * 5 g/ml = 
<gadget id="calculator">100*5</gadget>
<output>500</output>
500 g.
Do the same procedure with the weight and weight/volume ratio of the vinegar to find its weight: 50 ml * 4 g/ml = 
<gadget id="calculator">50*4</gadget>
<output>200</output>
200 g.
Now add the weight of the oil and the vinegar to find the weight of the salad dressing: 500 g + 200 g = 
<gadget id="calculator">500+200</gadget>
<output>700</output>
700 g.

<result>700</result>