Answer :
Pineapple tarts = 4/9
Coconut tarts = 1 - 4/9 = 5/9
gave 1/2 of the pineapple tarts
1/2 x 4/9 = 2/9
Pineapple tarts left = 4/9 - 2/9 = 2/9
gave 2/5 of the coconut tarts
2/5 x 5/9 = 2/9
Coconut tarts left = 2/5 - 2/9 = 8/45
Tarts left = 2/9 + 8/45 = 2/5
2/5 = 60 tarts
1/5 = 60 ÷ 2 = 30 tarts
5/5 = 30 x 5 = 150 tarts
He baked 150 tarts
Coconut tarts = 1 - 4/9 = 5/9
gave 1/2 of the pineapple tarts
1/2 x 4/9 = 2/9
Pineapple tarts left = 4/9 - 2/9 = 2/9
gave 2/5 of the coconut tarts
2/5 x 5/9 = 2/9
Coconut tarts left = 2/5 - 2/9 = 8/45
Tarts left = 2/9 + 8/45 = 2/5
2/5 = 60 tarts
1/5 = 60 ÷ 2 = 30 tarts
5/5 = 30 x 5 = 150 tarts
He baked 150 tarts