in cliff ’ s impressive rock collection , there are half as many igneous rocks as sedimentary rocks . of the igneous rocks , 3 / 4 are shiny and the rest are matte , while 1 / 5 of the sedimentary rocks are shiny . if there are 30 shiny igneous rocks , how many total rocks does cliff have ?
"we can start with the known quantity and then go on to find the others . shiny igneous ricks are 30 . these are ( 3 / 4 ) of total igneous rocks . ( 2 / 3 ) * total igneous rocks = 30 total igneous rocks = 30 * ( 4 / 3 ) = 40 total sedimentary rocks = 2 * total igneous rocks = 2 * 40 = 80 total number of rocks = 40 + 80 = 120 answer ( d )"
divide(multiply(divide(multiply(multiply(3, 4), 30), 3), 4), 3)