A tree had 1000 leaves before the onset of the dry season, when it sheds all its leaves. In the first week of the dry season, the tree shed 2/5 of the leaves. In the second week, it shed 40% of the remaining leaves.  In the third week, the tree shed 3/4 times as many leaves as it shed on the second week. Calculate the number of leaves the tree hadn't shed by the third week.
How many leaves did the tree shed in the first week? ** In the first week, the tree shed 2/5*1000 = <<2/5*1000=400>>400 leaves.
How many leaves were left on the tree at the end of the first week? ** The number of leaves remaining on the tree at the end of the first week is 1000-400 = <<1000-400=600>>600
How many leaves did the tree shed in the second week? ** In the second week, the tree shed 40/100*600 = <<40/100*600=240>>240 leaves.
How many leaves were left on the tree at the end of the second week? ** The number of leaves remaining on the tree is 600-240 = <<600-240=360>>360
How many leaves did the tree shed in the third week? ** The third week the tree shed 3/4 of its leaves, a total of 3/4*360 = <<3/4*360=270>>270 leaves.
How many leaves were left on the tree at the end of the third week? ** The number of leaves remaining on the tree is 360-270 = <<360-270=90>>90 leaves.
#### 90