Maya has 2x as many white beads as black beads. After using 40 white and 5 black to make a necklace she has 3x as many black beads as white. How many black beads she started with?

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Answer 1 · 2016-09-26T06:15:39

She started with #23# black beads.

Suppose Maya has #B# black beads and so has #2B# white beads.

She used #5# black beads and #40# white beads,

so she was left with #(B-5)# black beads and #2B-40# white beads.

Now as she has #3# times as many black beads as white,

#B-5=3xx(2B-40)# or

#B-5=6B-120# or

#120-5=6B-B# or

#5B=115# i.e. #B=115/5=23#

Hence, she started with #23# black beads.