brad walked to the shore There he saw 4 rocks lying side by

brad walked to the shore. There he saw 4 rocks lying side by side. Resting on the rocks were crabs. Each rock had 2 more crabs than the rock to its left. There were 56 crabs in all. how many crabs were on each rock?

Solution

Lets number the rocks from left to right 1 to 4.

let the crabs on rock 1 be x

then crabs on rock 2 =x+2

similarly crabs on rock 3=x+2+2=x+4

crabs on rock 4=x+4+2=x+6

total crabs =4x+6+4+2=4x+12=56

so 4x=44 and x =11

crabs on rock 1 =11

on rock 2 =13

on rock 3=15

on rock 4=17