Below is an instruction that describes a task. Write a response that appropriately completes the request in Swahili. Please answer in Swahili.

### Instruction:
At his craftwork store, Howard has a collection of 70 wooden bowls where he rewards two to his customers for every 10 they buy. If he had 20 customers that day, half of whom bought 20 bowls each, calculate the number of bowls remaining in the rewards collection.

### Response:
 Nusu ya wateja 20, ambayo ni 1/2*20=10 walikununua mabakuli 20 kila mmoja, wakipokea 2 kwa kila 10.
Jumla ya mabakuli ya zawadi ambayo kila mteja aliyenunua mabakuli 20 alipokea ni 2+2=4
Ikiwa wateja 10 walikununua mabakuli 20, Howard alitoa mabakuli 4*10=<<10*4=40>>40 kama zawadi.
Jumla ya mabakuli ya zawadi ambayo Howard alikuwa nayo ni 70, hivyo sasa ana mabakuli 70-40=<<70-40=30>>30 yaliyobaki.